Chapter III: Preface (2)

Today we have a few facts about early man and many guesses. Not so long ago there were a few reputable anthropologists who believed that the New World was innocent of man before 1000 B.C. Now most of them grant a foothold at least 10,000 years ago to an enterprising savage—called Folsom man—whose taste for travel was as great as his talent for making an exceptionally fine and original type of stone spear point. Some say he came to the New World 25,000 years ago. A few daring students find traces of an earlier Australoid human who may have seen the last glaciers taking shape. Well informed opinion places man’s entrance into the New World between 10,000 and 25,000 years ago.

Of course we must not expect early dates to be precise. Many of them must be intelligent guesses as we go deeper and deeper into the past and reach the time when the glaciers were waxing and waning. To gain a perspective upon such toying with time—as well as upon early man in the Americas—we must next consider the story of early man in the Old World. Incidentally, its contradictions and uncertainties—prefaced by a few in New World prehistory—may help you to look with a charitable as well as critical eye upon certain theories about the peopling of the Americas which may be suspect today yet respectable tomorrow.

3
THE DEAD HAND OF THE AGES

... _systems into ruin hurl’d_.
—ALEXANDER POPE

Conflicts and Confusions

The authors are afraid that it may be a little hard for you, dear reader, to shake yourself out of the late Victorianism of your schoolbooks and accept the idea that someone discovered America at least 14,092 years before Columbus. It may be still harder for you to believe that he was not that noble yet very vague red man whom you and your teachers called the American Indian. Certainly you will be shocked to hear that two or three anthropologists of note believe he had more than a touch of Negroid or Australoid blood. Your horror will be no greater, however, than that of a few of our archaeologists; such notions give them what might be called Victorian vapors. Some accept ideas like these; others keep an open mind, for they remember that many a scientific fact of today was sheer nonsense to earlier generations, and vice versa.

As late as 1900, the prehistory of Mexico was accounted for very neatly by three successive words, Toltec, Chichimec, and Aztec. Now we know other words, and we know that other peoples and other cultures—Olmec, Zapotec, Mixtec, Totonac, Tarascan, Teotihuacan—also played an important part. We divided the Maya just as neatly into the Old Empire and the New, one south and the other north. Now we know that there were no empires, and that the Maya culture grew widely and steadily towards fruition and decay. Once we thought that the Itzá were the Maya that founded Chichén-Itzá in Yucatan. Now we give the name Itzá to the Toltec or Toltec-influenced invaders that came hundreds of years later. Once scientists disputed whether culture and agriculture began in the highlands of Mexico or in the highlands of Peru. Now certain of them believe that the American became a farmer in the lowlands east of the Andes, while others think he began to till the soil in many spots at the same time. Only a few years ago, we thought that a fairly recent Indian culture—which is called the Woodland Pattern of the eastern United States—had its roots in Middle America. Now its pottery is being traced back through northwestern Canada and northern Asia to the Baltic and even perhaps to Africa.[1] The Mound Builders were once thought an ancient people. Now some of them seem barely to antedate the discovery of America. Bernal Díaz del Castillo—best of the chroniclers of the conquest of Mexico—may have observed that the Mexicans, along with all the Indians of the New World, were ignorant of the principle of the wheel; certainly this has been repeated over and over again for many years. Yet in 1888 Désiré Charnay reported and pictured a Mexican pottery toy with wheels, and since then more of these toys have been found.[2] Throughout his life Roland B. Dixon denied the possibility of productive transpacific migration from Polynesia to South America; yet at the end he accepted the transfer of the sweet potato from South America to Polynesia. From important matters to trivia, the list is long; we have hardly touched it. Obviously, prehistory is not a field where truth is easily and quickly come upon. The student, quite as much as the scientist, must keep an open mind. He must neither cherish dogma nor refuse speculation. Truth still lies afar off.

Doubts about early man in the Americas seem to have been an occupational disease with archaeologists. Geologists have found it much easier to accept him. Men like Ernst Antevs, M. M. Leighton, Kirk Bryan, and Albrecht Penck, perhaps because they are accustomed to dealing generously with time, seem to have little trouble in embracing early man as a Late Glacial interloper anywhere from 15,000 to 100,000 years ago. Physical anthropologists like Earnest A. Hooton and Sir Arthur Keith, and cultural anthropologists and ethnologists like Roland Dixon and A. C. Haddon are not at all afraid to recognize signs of Australoid or Negroid ancestry in the skulls of New World man. Perhaps it is easier for the geologists and the physical anthropologists to accept such ideas because they do not run counter to their own dogmas. Many archaeologists, at any rate, find it extraordinarily hard to adjust themselves to evidence which does not fit accepted theories. They may defend themselves by pointing out that the evidence is not too clear, or at best is merely suggestive; but the theories they cherish arose from no firmer evidence in many cases, and frequently continue quite as unclear or at best merely suggestive. Certainly such reluctance to accept new evidence held back archaeological research when Aleš Hrdlička, W. H. Holmes, and Daniel G. Brinton were in their heyday.

This reluctance to face facts permeated even so great and productive a man as Baron Erland Nordenskiöld. An example of such a Jovian nod may be salutary. Arguing in _The Copper and Bronze Ages in South America_ against the theory that the craft of metallurgy may have been brought to the New World by migrants, instead of having been invented here, three times he cites facts that contradict his thesis, and three times he offers a kind of self-conscious apology for blinking them. (The italics are ours.)

If we go through all our material of weapons and tools of bronze and
copper from South America, _we must confess_ that there is not much
that is entirely original, and that to the majority of fundamental
types there is something to correspond in the Old World.

_It must be confessed_ that there is considerable similarity between
the metal technique of the New World and that of the Old during the
Bronze Age.

Bronze is, of course, also a very hard invention, and _I must confess_
to finding it most remarkable that the art of alloying tin and copper
should have been hit upon independently both in the Old World and the
New.[3]

“Admissions,” said Charles John Darling, “are mostly made by those who do not know their importance.”

Unfortunately there are still a few archaeologists whose attitude resembles Nordenskiöld’s. Hooton writes of one of these:

One of our most brilliant and once progressive archaeologists naïvely
expressed to me some years ago his sentiments on this question
[evidences of early man in America]. He said it would be a pity to
have new evidence come to light which would overthrow all the
admirable scientific work of the past indicating the recent arrival in
the New World of the American Indian.[4]

Of course early man is not a subject that can hope to be free from error and contradiction—even early man in the Old World. Perhaps an account of some of the errors and misconceptions about him that crept into the study of prehistory may be as good a means as any of preparing your mind for new facts or new heresies in the Americas.

The Problem of the Ages

The first confusion that confronts the student of early man is one of nomenclature. It is a by-product of the human animal’s inveterate and estimable love of system. Give us some new subject, such as prehistoric relics, and we immediately set up a scheme of classification. The scheme works beautifully for a while, but presently new evidence accumulates which doesn’t fit the framework. By that time, unfortunately, it is too late to change the classification. In vulgar parlance, it is our story, and we are stuck with it.

An outstanding example of this tendency to set up a classification system prematurely is the division of the story of man into ages. As far back as A.D. 52 a Chinese with a scientific bent of mind suggested that man had passed through three periods: a stone age, a bronze age, and an iron age. A French magistrate named Goguet wrote a book in 1758 in which he expounded a similar order of ages, inserting copper ahead of bronze. In 1813 a Dutch historian named Vedel-Simonsen argued for stone, bronze, and iron periods in Scandinavian history. A Dane, Christian Jurgensen Thomsen, gave the system permanent and indeed international status in 1836 when he arranged on this basis the exhibits of the institution he directed, the National Museum in Copenhagen.

The scheme is neat but far from scientific. To begin with a small matter, but one that may confuse the layman, the ages overlap. Bronze did not wholly replace stone; neither did iron. The use of chipped flint and polished stone continued into the Iron Age.

The Bronze Age—a Phantasm

“Bronze Age” itself is a misnomer and a phantasm. While “Stone Age” and “Iron Age” do define important culture periods—though not the only periods of man’s early activity—the Bronze Age, says T. A. Rickard, “represents a minor phase in the use of copper.”[5] This alloy is merely an incident in the much longer history of the first metal used by man. At the start copper seemed to him to be merely a soft stone. He beat it into ornaments. When he began to melt and cast the native metal instead of pounding it, he took the first step in the true use of metals; but when he smelted copper ore—turning a hard rock into a soft metal—he made himself the master of metallurgy. Bronze—at first an accidental mixing of copper and tin—was merely an episode along the way. “The superiority of copper or bronze over flint and stone tools is, I think,” says Gordon Childe, “generally overestimated. Not only for tilling the land but also for the execution of monumental carvings and even for shaving, the Egyptians of the Old Kingdom were apparently content with stone.”[6]

The Bronze Age was very limited in area. Because of the rarity of tin, the primitive use of the alloy was confined to southern Europe, Asia Minor, and the Inca empire. Most of the world used iron before bronze. Furthermore, the Bronze Age is as delimited in time as it is in space. The earliest bronze in the Danube region is dated about 2300 B.C., and the earliest iron about 1350 B.C., at Gerar in Judea. “Thus,” said Rickard, “the so-called Bronze Age shrinks, at most, to a mere millennium ... the merest fraction of human existence.”[7]

The Iron Age is not so significant as it sounds. It was many centuries after the first use of iron and bronze that either played a really important part in the economic life of man. Like the domesticated horse, the trained elephant, and the wheeled vehicle, bronze and iron were first used chiefly in the making of war.

Wood, Bone, and Shell Ages

There is another serious weakness in the Stone Age, Bronze Age, Iron Age sequence. It takes no account of the probability that man used wood, bone, and shell before he used stone. The ape swings a stick much as the first man must have done. The carcass of some bison or stag, picked clean by vultures, must have seemed to our earliest ancestors “a whole potential tool-shop”—as George R. Stewart writes in _Man: An Autobiography_—“thigh bones ready-made for clubs, horns or antlers for awls, shoulder-blades for scrapers.”[8] As early as 1864, a British student of anthropology, John Crawfurd, stood out against Thomsen’s Stone Age as the beginning of culture. At a meeting of the Ethnological Society, he said: “On man’s first appearance, the most obvious materials would consist of wood and bone.... This would constitute the wood and bone age, of which, from the perishable nature of the materials, we, of course, possess but slender records.”[9] Because the discovery of the stone artifacts of early man in Europe was then creating a scientific furore, Crawfurd’s sane observations went unnoticed. Today we have part of a wooden spear made, perhaps, far back in the Great Ice Age (see illustration, page 74).

Wood, bone, and shell not only antedated stone; they have continued in use until today. Certain primitive peoples—the Chukchi of Siberia, for example—retained the use of wood and bone after they were given iron.[10] Numerous tribes, when first encountered by explorers and navigators, had not yet begun to use stone; among these were the Aleuts, the Andaman Islanders, Malayans from the hills, and people of the upper Amazon.[11]

Rickard, from whom we have drawn liberally in this discussion, proposes a different scheme of classification for the cultures of man.[12] In the Primordial Age he would include the primary use of wood, bone, and shell. He would accept the Stone Age as the next stage. For the Bronze and Iron ages he would substitute the Metallurgic Age, basing this on the discovery and use of smelting, whatever the metal involved. The dead hand of Thomsen, however, will probably continue to rule. The best we can do will be to take the Stone Age as including all materials except metal, and pay little attention to that illusion the Bronze Age.

Dividing the Stone Age—the Old and the New

Still more conflict and confusion have resulted from attempts to divide the Stone Age into watertight compartments. In 1865 Sir John Lubbock proposed two divisions—the Paleolithic, or Old Stone Age—and the Neolithic, or New Stone Age.[13] The Paleolithic included objects found in caves and glacial gravels; the Neolithic, on the surface and in tombs. The first period ran from some vague beginning hundreds of thousands of years ago up to the advent of the Neolithic after the glaciers had melted. By definition, paleolithic man made chipped stone implements and no other kind. Neolithic man was supposed to be distinguished by the making of ground, or—as we usually say—polished, stone axes and of other tools shaped by rubbing instead of chipping; agriculture, pottery, and textiles came in as secondary traits.

After a time, however, archaeologists found some disturbing discrepancies. Before neolithic man grew grain and wove textiles, someone of an earlier age seems to have been making axes from antlers, turning out new artifacts called microliths—tiny chips of flint which were set in a row along a wooden or bone handle to make a kind of saw or a sickle—and also producing a partially polished ax with a ground edge, and making crude pots. This was all very upsetting to the old scheme of dividing prehistory into the Paleolithic and the Neolithic. So science inserted the Mesolithic, or Middle Stone Age, between the two, in order to account for the appearance of the new tools.

The trouble with the system that Lubbock launched is that man’s behavior toward stone is a very poor basis for classifying him in culture or time. For a while it fitted our knowledge of the prehistory of Europe. Now it is out of line on that continent, and completely askew so far as the rest of the world is concerned. The kind of stone available often determines whether a man will chip or grind it. When first discovered, South Sea Islanders were still polishing stone because they had no flint.[14] Some Australian natives make chipped stone tools while their neighbors, who control a supply of diorite, go in for polishing; yet none of these Blackfellows can be considered as anything but paleolithic.

Like the Bronze Age, the Neolithic suffers from having shrunk in length. Rickard figures “that 700 years covers what was meant to be a major division of human chronology.”[15] To reach this figure he puts the end of the Paleolithic at 3000 B.C., which seems much too late, and the beginning of bronze at 2300. Even though we use the date of N. C. Nelson for the beginning of the Neolithic—5500 B.C.[16]—we have a New Stone Age of only 3,200 years.

Gordon Childe goes so far as to declare that “there is no such thing as a neolithic civilization.”[17] Different people, living under different climates and on different soils, have developed different elements of the culture of the New Stone Age and combined them with elements of other cultures.

If we are going to continue using the term Neolithic—as we certainly are—and if we want to limit it in some sensible way that may prove a bit more permanent, let us see what else than polished stone can be used to define it.

Activities of the New Stone Age

Three activities stand out. They are the making of pots, the weaving of textiles, and the planting and harvesting of crops accompanied by the domestication of animals.

There can be no question that pottery is an important factor in neolithic life. It was in the New Stone Age that man fully wrought the miracle of “a sort of magic transubstantiation—the conversion of mud or dust into stone,” as Childe puts it. It was, as he says, “the earliest conscious utilization by man of a chemical change.”[18] But behind this miracle and this science must have lain many years of almost accidental, adventitious experiment. L. S. B. Leakey claims specimens of partially baked pottery sherds in paleolithic Africa.[19] One of these shows marks of basketry, rather thin support for the theory that the women who daubed the inside of the baskets to make them hold water must have discovered, when the baskets stood too near the fire, a little bit about how to bake clay. It was not until the invention of agriculture tied neolithic man more or less to the soil that true pottery could and did flourish widely. We have added many refinements to the craft of the potter—porcelain, cloisonné, and so forth—but basically it remains unchanged. Incidentally, all agriculturists did not have pottery—the Big Bend and Hueco cave dwellers of Texas, and certain people of the Virú valley in Peru, for example.[20]

The craft of textile weaving almost reached perfection at the hands of neolithic man—or, rather, woman. But it stemmed from basketry, and basketry undoubtedly began in the Paleolithic Age.

The first of two interesting facts suggested by the foregoing is that woman was the only true begetter of the Neolithic Age. She did the weaving—first of baskets and then of textiles—and she invented and practiced pottery making. More than that, she must be credited with the planting and harvesting of grain; for, while her lord and master enjoyed himself on the hunt, she gathered fruits, nuts, and edible seeds, and sooner or later this led her to observe that seeds she carelessly dropped on the midden pile produced new and bigger plants. By so doing woman invented work; for early man was only an idler who gave himself intermittently to the pleasures of the chase. Woman also invented leisure—true, creative leisure—for out of agriculture rose a settled community and a surplus of provender which allowed the few to think and plan and build civilization.

Agriculture—Test of the Neolithic

The second fact is that agriculture seems to be the only sound test of the Neolithic. Pottery and weaving preceded agriculture, yet, without agriculture and its fixed communities and its leisure, pottery and weaving could not have reached perfection. As for the polished ax, it was handy enough in in-fighting; but it was of no practical social use until the farmer needed to cut down the trees which began to thrive all over the place when the glaciers disappeared. The Badarians of Egypt were farmers, yet they made no polished axes because there was almost no timber to cut.[21]

Speech was certainly the first great inventive triumph of primitive man. The making of fire ranks second. The third great invention, agriculture, was also the first industrial revolution; without it what we carelessly assume to be _the_ industrial revolution would have been impossible.

Science feels sure that agriculture appeared in the Old World before it did in the New, but is not so certain as to where man first tilled the soil and when. James H. Breasted, Sr., put agriculture back to 18,000 B.C.; later writers push it up to 5000 B.C. There has been quite as much disagreement about the area where agriculture began. At first the valley of the Nile seemed to be the right spot, for every fall the flood waters of the river brought not only automatic irrigation but also fresh, fertile soil to enrich the depleted farm lands. Soon, however, the birthplace of agriculture moved to the “fertile crescent” that stretched from Egypt to Mesopotamia. Later it shifted from the Tigris-Euphrates valley to the valley of the Indus. Now it seems to lie somewhere between these two, perhaps in the dry highlands of Iran and Iraq. In northern Iraq, 400 miles north of Ur, the wild ancestors of certain of our cultivated grains still grow, and excavators have come on evidences of farming communities which may be 8,000 to 11,000 years old.[22] There has always been hot argument between the supporters of denuded river valleys and the supporters of dry uplands as the natural site of early agriculture. Lately students have begun to argue for forested or jungle areas, and above all for mountain valleys; and they have plumped for tubers and melons, rather than grains, as the first crops cultivated by early man. These students see man as a gardener before he was a farmer.

Only the beginnings of agriculture are of any importance in a discussion of early man. Early man may invent agriculture, but thereupon he promptly ceases to be early man. With the food, leisure, and fixed abode that farming provides, he is soon inventing writing. He is then no longer even prehistoric.

First a Food Gatherer, Then a Hunter

It is important to realize and remember that early man ate seed grains, tubers, and fruit before he knew how to cultivate them. Probably he began to eat more and more of these natural products just before he became a farmer. Because archaeologists have found evidences that early man was quite a food gatherer at the end of his career, they have been inclined to set up another classification system which is faulty. They see man first as a hunter, then as a food gatherer who was still a hunter, and then as a food producer. This ignores the very important fact that man began as a food gatherer and not as a hunter.

The first man probably ate the same food as the great ape—fruits, nuts, roots, and berries—and perhaps grubs and insects. Occasionally he may have varied his repast with birds’ eggs and fledglings. With a broken branch for a weapon, he improved his diet a bit. He knocked over small animals, and he may occasionally have got hold of the carcass of a large one, but, for thousands upon thousands of years, he was basically a vegetarian. His first well developed stone tool—the hand ax shaped rather like a flattened and pointed egg—was probably more useful for grubbing roots and tubers out of the ground than for killing animals. As early man learned to make more efficient weapons—first the curved throwing stick, then the spear and the spear-thrower, and finally the bow and arrow—hunting became his chief activity, and meat his chief diet. But his woman went right on gathering berries and nuts, tubers and seeds, and getting ready to invent agriculture. Certainly in the New World—perhaps in the Old World, too—she invented milling stones to grind seeds while her man was still a paleolithic. Perhaps when she watched the wearing away and the smoothing down of mortar and pestle, milling stone and mano, as she ground her seeds into flour between them, the idea may have occurred to her—or to her man who watched her labor—that it was possible to grind and polish stone into axes and other implements.

We feel that the life-story of prehistoric man can best be divided—certainly for the purposes of this book—into a Paleolithic, or Old Stone Age, which included the making of artifacts out of wood, bone, shell, and chipped and sometimes polished stone, and a Neolithic, or New Stone Age, which was defined by the invention of agriculture and the perfecting of pottery, of weaving, and of the polishing of stone. This may reduce a little the confusions that are inevitable in the study of early man tens of thousands to hundreds of thousands of years ago. Conflicts of evidence and opinion will remain, of course. We need not let them deter us from judging early man in the Americas. Indeed, they should free us from paying too much heed to the dogmas of scientific conservatism.

4
THE GREAT ICE AGE

_Speak to the earth, and it shall teach thee._
—JOB 12:8

Our Part of the Geologic Time Scale

The dead hand of another system of classification lies across a still larger area than the Stone Age itself or the Age of Man. This area is the entire life of our earth since it took sufficient shape to support cellular life. As it is so large an area and much of it is so remote in time, changes in the definition of most of its various divisions do not much affect the present discussion.

Once upon a time there were four great divisions, neatly numbered in Latin as the Primary, the Secondary, the Tertiary, and the Quaternary. The first two went by the board when newer scientists found older ages and stretched the life of the earth a couple of billion years. The Tertiary is still a respected appellation, but the good name of the Quaternary—the area of time with which this book is mainly concerned—is seriously questioned. Defined as the Age of Man, it was supposed to harbor all evidence of his existence; but hints of his presence in the Tertiary have rather sullied the scientific standing of the later period.

_This summary of the story of the earth is a combination of charts
in Arthur Holmes’_ Principles of Physical Geology, _Earnest A.
Hooton’s_ Up from the Ape, _and George Gaylord Simpson’s_ The
Meaning of Evolution, _with modifications by William C. Putnam and
James Gilluly. *The divisions marked with an asterisk used to be
called, respectively, Secondary and Primary._]

PALEONTOLOGICAL DIVISIONS GEOLOGICAL DURATION IN CUMULATIVE
DIVISIONS YEARS TOTALS
(_Round
numbers_)

CENOZOIC (“recent life”)
_Quaternary_ Holocene 25,000
Age of Man (“wholly recent”)
Pleistocene 1,000,000 1,000,000
(“most recent”)
or Great Ice Age
_Tertiary_ Pliocene 11,000,000
Age of Mammals (“more recent”)
Miocene 16,000,000
(“less recent”)
Oligocene 11,000,000 75,000,000
(“little recent”)
Eocene 19,000,000
(“dawn of recent”)
Paleocene 17,000,000
(“ancient recent”)
MESOZOIC (“middle life”) Three periods 130,000,000 205,000,000
*Age of Reptiles
PALEOZOIC (“ancient life”) Six or seven 300,000,000 505,000,000
periods beginning
with the Cambrian
*Age of Fishes, Amphibians, and Primitive
Marine Invertebrates
PROTEROZOIC (“earlier life”) Pre-Cambrian 1,250,000,000 1,750,000,000
Age, presumably, of soft-bodied animals
ARCHAEOZOIC (“primordial life”)
EOZOIC (“dawn of life”)
Problematic signs of life, indicated by
presence of carbon
Unrecorded Interval Since the Origin of the Unknown 2,000,000,000
Earth to
10,000,000,000

In this book we are concerned with two divisions of the Quaternary which are also growing vaguer in outline, less precise in time. They are the Pleistocene, or Glacial Period, or Great Ice Age, and the Holocene, Recent, or Postglacial Period in which we now live. (If your Greek is rusty, you will be amused to discover that those scientific-sounding terms are merely translations of “wholly recent” and “most recent.”) Most geologists believe that these two areas of time covered about 1,000,000 years; but some give them half a million more, and a few limit them to the 600,000 years, or even 300,000 years, of the last four glaciations. Some start the Postglacial 25,000 years ago, when the ice began to shrink toward its present limits; some start it 9,000 years ago, when a relatively modern climate appeared. Some geologists say we are still in the Pleistocene, and merely enjoying a warm spell before another glaciation.

By definition—or lack of it—the Pleistocene is rather vaguely bounded, and quite as much at its beginning as at its end. To the paleontologist, the Pleistocene is the time of certain large and picturesque mammals that are now extinct. To the geologist, it is the time of the waxing and waning of the great glaciers. The beginnings and the ends of these two definitions of the Pleistocene do not correspond too closely. We shall use the term as little as possible, substituting the Great Ice Age.

The Glacial Hypothesis Appears

It is hardly more than a century since science began to realize that large parts of Europe and North America once were covered with glaciers. The discovery came from attempts to explain certain disturbing things called “erratic blocks.” These were large masses of stone—sometimes weighing as much as 10,000 tons—which had no business being where they were, because the native rock in their neighborhood was entirely different. Some of the erratic blocks, for example, should have been hundreds of miles away. The common explanation was that they were water-borne, perhaps by the biblical flood. An American cotton manufacturer accounted for the wearing away and the scratching of such boulders by supposing that they had been embedded in the lower surfaces of icebergs and then swept scraping across the earth by the tumultuous waters on which the Ark had ridden. In 1802 John Playfair, a professor of mathematics at Edinburgh, ventured the theory that the blocks had been transported by glacial ice.[1] This idea had occurred to a mountaineer named Kuhn in 1787, and Saussure echoed it in 1803; they knew and interpreted correctly the moraines of loose stones and boulders which they saw at the foot and the sides of the glaciers. From 1821 to the middle thirties various French, Swiss, and German scientists—Brard, Venetz, Charpentier, and Schimper—discussed and amplified this idea. Though A. Bernhardi, an obscure German professor of forestry, suggested in 1832 that “the polar ice once reached clear to the southernmost edge of the district which is now covered by those rock remnants,”[2] it was not until 1837 that the glacial theory took definite shape. Then Louis Agassiz, speaking before a Swiss society, launched the glacial hypothesis that there had been a period of great cold just before the advent of recent life. By 1840, when Agassiz published his _Studies of the Glaciers_, the idea was pretty generally accepted; he had “added the Glacial Epoch to the geological time-table.” The theory has been much amplified since then.

Adolphe Morlot, in 1854, discovered fossils of temperate plants between layers of glacial deposits, and advanced the theory that there had been warm periods as well as cold ones during the Great Ice Age. In his “Notice sur le Quaternaire en Suisse” he suggested three separate glaciations with two warm interglacial periods between. In 1874 James Geikie, the geologist of Edinburgh, brought out his _The Great Ice Age and Its Relation to the Antiquity of Man_, building upon Morlot’s work; and his _Prehistoric Europe_, in 1881, expanded the glaciations to six. Yet for thirty more years some stubborn scientists still believed in a single glaciation.

It was not until the turn of the century that the work of Albrecht Penck and Eduard Brückner established the history of the Alpine glaciations on a solid scientific foundation that has endured pretty well till today. They found four major glaciations and named them in neat alphabetical order after four Alpine valleys—Günz, Mindel, Riss, and Würm.[3] They divided the Würm glaciation at first into two periods of activity, and later into a number of smaller oscillations toward the end. There has been some controversy over the subdivisions of the Würm, and one to three Danubian glaciers have been suggested hundreds of thousands of years before the Günz; but the general hypothesis brought forward by Agassiz and the amplifications of his successors are now definitely established. With all this goes much knowledge of the ice sheets that covered Scandinavia, northern England, and Germany as far south as Dresden, and North America from ocean to ocean and down to Long Island and the Ohio and Missouri rivers.

The End of the Great Ice Age

Authorities agree that the last melting of the ice sheets and glaciers in the Alpine region began somewhere between 20,000 and 15,500 years ago. After considerable shrinkage and oscillation, the ice increased again for about 5,000 years, and then began to shrink once more. There is some disagreement as to when the Great Ice Age ended; a recent and very minor Daun glaciation has been rather rashly dated as late as only 3,500 years ago. These calculations are only for the Alpine region, and we must remember, of course, that the great ice sheets of northern Europe and North America behaved somewhat differently.

_At the height of the last glaciation 5,000,000 square miles of
North America were covered with ice, as against 2,500,000 in
Eurasia. The volume of ice was three times as great. The shore lines
are those of the present rather than glacial time. (Map after Flint,
1957; Antevs, 1928; and Flint and Dorsey, 1945; estimates from Daly,
1934.)_]

We have some fairly exact knowledge about the retreat of the ice across Sweden. This has resulted from the theory of Baron Gerhard de Geer that the varves—layers of alternately coarse and fine clays deposited in lakes in front of the retreating glaciers—represent the summer and winter sediments released by the melting ice. (We have a somewhat similar index in the tree-ring count of wide and narrow rings originated by A. E. Douglass and improved upon by Harold S. Gladwin. Both tree rings and varves may reflect changes in solar radiation.) De Geer counted the varves and determined that the ice sheet began to retreat in southernmost Sweden some 14,000 years ago, and Ragnar Liden determined that it had disappeared by 6840 B.C.

De Geer’s Swedish-American pupil Ernst Antevs applied the same system in North America, and found the ice beginning to retreat from Long Island 36,500 years ago.[4] A calculation of the time required for the wearing away of the postglacial Niagara Gorge has produced about the same result, but this has been seriously challenged by Richard F. Flint.[5]

The picture of glaciation is more complicated in North America than in the Old World. Europe had two main areas of ice—a small one in the Alps, a much larger one in Scandinavia, the British Isles, northern Germany, and Poland—but they were self-contained. North America had three ice centers—the Labradoran east of Hudson Bay, the Keewatin west of the bay, and the Cordilleran in the Canadian Rockies; these three sheets of ice did not always grow or shrink at the same time or at the same rate, and they occasionally overlapped (see maps on pages 26 and 27).

Incidentally, most of the ice of the glacial period was in the New World. The area of land covered was almost twice as great as in the Old World, and the bulk of ice three to five times as great.[6]

River Terraces and Beach Lines

There are other evidences of glaciation besides varves, erratic blocks, moraines of stones and mixed debris along the sides and fronts of the ice streams, and scratches and polish on the native rock over which the glaciers passed. Four raised terraces are found along the sides of many river valleys. Four raised beach lines, first found in the Mediterranean region, have now been noted in the Americas and Australia. Submerged beach lines and land-bridges have been found at certain places under the ocean, as well as deep channels prolonging present rivers far out to sea.

Naturally enough the Great Ice Age was a time of notable changes of climate. Vegetation advanced and retreated widely. The level of the sea rose and fell some hundreds of feet. Whether or not there was more rain and snow—a moot point with science—the many rivers of the world grew in volume, and often in speed, at certain times and became low and sluggish at others. These profound alternations created the river terraces which have aided so much in determining the age of man and his various cultures. As the ocean sank, while the glaciers grew, the slopes of river beds became steeper, and the rivers themselves grew swifter. The turbulent rivers cut deeper channels and carried the displaced materials far down their valleys and ultimately even into the sea. During the cold, dry period at the climax of each glaciation, the dying trees and brush and grasses released their grip on gravels and silts, the intermittent flood waters of the melting glaciers carried away the debris and—because the rivers lost in slope and grew sluggish as the sea level rose—they deposited the gravels and silts in their beds. As the glaciers grew again and the oceans sank, the rivers once more became swifter and more turbulent, cut deeper channels, carried away part of the gravels and silts, and left the rest as terraces. Thus the passing of each glaciation meant the adding of a new and a lower terrace to the river valleys. Four such sets of river terraces are found just outside the areas where the glaciers have been active—in the valleys of the Rhine, the Thames, the Somme, the Isar, and other rivers.

_These simplified sections of a river valley show how successive
channels were cut deeper and deeper, leaving the older deposits of
gravels and silts in the higher terraces at the sides. The discovery
of this process of nature was of the greatest value in determining
the age and the succession of the cultures of early man in Europe.
The oldest flint tools were found in the gravels of the highest
terraces, and the newest in the lowest._]

Farther to the south, periods of great rainfall helped to produce similar river terraces in valleys like the Nile. The concentration of masses of ice in central and northern Europe upset the zones of climate of Africa and other parts of the earth and caused great climatic disturbance. Rainfall belts moved far south, and the rain increased in abundance. Such periods of rain are called pluvials. There is still a good deal of argument about whether pluvial periods occurred principally in glacial or interglacial periods. This affects the dating of early man, and it is particularly important to us in the New World.

The raised beaches and the submerged beaches were obviously caused primarily by the lowering and raising of the sea level and not of the land. There were land movements, of course—as there are even now—but they were either too small or too irregular to account entirely for the systematic arrangement of old beaches in many parts of the world.

There has been much controversy about other glacial matters, but there can be no question that the submerged beaches and the land-bridges were a by-product of glaciation. The great masses of ice—estimated to have averaged half a mile to two miles thick in North America and somewhere between those figures in northern Europe—depressed somewhat the parts of the earth on which they lay; the rest of the land tended consequently to rise a bit, though not enough to account for the now sunken beaches and for the land-bridges that united Africa and Europe, England and the Continent, and Alaska and Siberia at various times. It was the immense amount of sea water drawn up and locked in the glaciers that reduced the area of the ocean and created new shore lines and the land-bridges. Estimates of how much the seas were lowered from their present level range from 70 to 1,800 feet; the best are 200 to 300 feet. There is still enough glacial ice to raise the ocean more than 100 feet if it all melted.

The raised beaches belong to a later discussion of the cause of the Great Ice Age as a whole.

The Cause of Glaciation

Most geologists believe that a comparatively slight drop in temperature would bring back the glaciers and the ice fields. The German geologist Brückner calculated that summers in the last glaciation were only 4° centigrade, or about 7° Fahrenheit, colder than they are today.[7]

What could have caused this slight drop in temperature in the Great Ice Age? Most of the explanations are not satisfactory. One is that the earth happened to pass through a dust laden nebula that reduced solar radiation. Another is a hypothetical decrease in the amount of carbon dioxide in the atmosphere. Other explanations have to do with changes in the altitude of land, shifts in air currents and ocean currents, volcanic eruptions filling the air with dust that screened the rays of the sun. All these adventitious causes would have had to be repeated with the curious and complex rhythm which is characteristic of the waxing and waning of the ice sheets.

One theory seems to have a good deal of cogency. It depends on three known alterations in the relation of the earth to the sun. The first is a slow, regular change in the shape of the earth’s orbit through a cycle of 92,000 years. The second is a shift in the inclination of the earth’s axis through 40,000 years. The third is what a layman would call the wobble of this axis through 21,000 years. The first change increases or decreases the distance of the earth from the sun. The other two alter the angle of the sun’s rays and thus also increase or decrease the warmth given a particular area of the earth at certain seasons. No single unfavorable position would have had a great deal of effect in lowering summer temperature in the northern hemisphere, but two occurring at the same time—let alone three—would have appreciably diminished the sun’s heat.

This astronomical theory of the cause of glaciation goes back a hundred years. As long ago as 1842 the French mathematician and astronomer J. Adhémar suggested that changes in the earth’s axis increased rainfall and provided the floods which he thought had moved the erratic blocks. Between 1864 and 1875 James Croll combined the wobble of the earth’s axis and the change in the earth’s orbit. A number of other men worked unsatisfactorily on the problem. The Serbian astronomer and physicist Milutin Milankovitch combined all three, and, between his first publication in 1913 and his latest in 1938, calculated the variations of solar radiation for the past 650,000 years.[8] In 1924 W. Köppen and A. Wegener applied Milankovitch’s early figures to the glaciation question, and Frederick E. Zeuner has lately used the revised figures of Milankovitch. Zeuner’s results, somewhat simplified, appear on page 55. They are fairly close to the geological estimates of B. Eberl and W. Soergel; his last two glaciations extend further back than those of Penck and Brückner.[9] Zeuner’s dates do not agree, of course, with those of an extremist like the geologist Kirtley F. Mather, who dates the first, or Günz, glaciation as ranging from 2,000,000 to 1,500,000 years ago.[10] Zeuner’s findings work out well enough for the American glaciations, except that there is no New World equivalent for his first Würm maximum of 115,000 years ago. Many authorities refuse to accept any such condition in the Old World. Because of this glaciation Zeuner moves back the appearance of _Homo sapiens_ a good 50,000 or even 75,000 years.

_Six varying estimates of their duration made by five authorities.
Fisk’s are of the New World glaciers, which are generally equated
with those of Europe._]

There is one serious objection to Zeuner’s theory. Two of the three movements of the earth on which it is based would have reduced the warmth of summer in the northern hemisphere, but they would at the same time have increased the temperature of the southern hemisphere, thus alternating glaciation in the two hemispheres. Unfortunately, it is fairly well established that glaciers north and south of the equator have waxed and waned at the same time over a considerable number of years.

It is not enough, of course, to find the cause of the individual glaciations. There must be a cause for the glacial period as a whole. The Great Ice Age was an almost unique event in the history of the earth. We have to go back 200,000,000 years, to the time of the reptiles that preceded the dinosaurs, before we come again on major glaciations.

Zeuner states frankly that the astronomic theory “does not provide the cause of the Ice Age” as a whole.[11] Some added factor must be found. One which he considers is a migration of the north pole from the direction of the Pacific to its present location; Zeuner and others think the movement occurred before the Great Ice Age.

Two geologists, Maurice Ewing and William L. Donn, have accounted for the beginning of the Ice Age by accepting the theory that the north and south poles had moved from the north Pacific and the south Atlantic to their present positions. They account rather ingeniously for the advance and the retreat of the four glaciations. With the north pole where it is now, the ice-free Arctic Ocean would supply moisture by evaporation. This moisture, owing to cold over the northern areas of Asia and North America, would fall as snow to nourish glaciers. But how to stop this process and reverse it? It happens that the sea floor forms a rather high sill between the Atlantic and the Arctic Oceans. When the sea level dropped, as its water piled up in the great glaciers, the sill came too close to the surface to allow much of the warmer water from the Atlantic to reach the Arctic Ocean and to keep it from freezing over. Once the ice pack formed, evaporation diminished abruptly. The glaciers lost their nourishment. The summer melt returned their waters to the ocean. Sea level rose. The currents from the Atlantic could flow over the sill again and melt the ice pack. Then conditions would be ripe for a second advance of snow and ice across the northern world. The shallow waters of Bering Strait probably had little effect upon the Arctic Ocean.

This theory has been criticized adversely by various authorities, despite the geologic, oceanographic, and meteorological evidence that Ewing and Donn have brought to bear upon each step of their reasoning. Their theory is particularly attractive to the archaeologist; it requires an ice-free Arctic coast when the land-bridge at Bering Strait would have been available to early man. Climatic conditions at that time would have been severe along the land-bridge and coastline, but not impossible for the survival of early man.[12]

Another explanation is a general decrease in solar energy; Zeuner holds this in reserve for lack of evidence. But some present-day geologists seize on the possibility that the heat of the sun may have changed from time to time, and use the theory in a curious, almost paradoxical way. The author of this hypothesis, Sir George C. Simpson, believes that the great masses of ice resulted from an initial _increase_ instead of a decrease in temperature.[13] As the weather grew slightly warmer, cloudiness and rain and snow increased, the snow-line fell, and glaciation resulted. As the weather grew still warmer, the ice melted. (Simpson demonstrated the basic principle of this through an ingenious laboratory experiment.) His glacial theory, which is explained in more detail on the opposite page, postulates two increases in solar energy, and draws from them a meteorological pattern that provides the four glacial and three interglacial periods. The first and last interglacials would be warm and wet, the second cold and dry. Zeuner objects to this theory on the ground that the last interglacial—which, according to Simpson, should have been warm and wet—was mainly cool and dry.[14] But, while it may have been cool and dry in the German area which Zeuner has most closely studied, other areas probably had other climates. Simpson’s hypothesis would account for the heavy rains, or pluvial periods, of Nilotic Africa, which may link up with the glaciations of Europe; but he provides only two pluvials, and there are evidences of three or more in Africa.

_A somewhat modified graph of Simpson’s theory of the cause of the
Great Ice Age. The following summary by Carl Sauer includes
quotations from Simpson: [First] “Increased solar radiation received
by the earth leads to increase in the general circulation of the
atmosphere, which forms a great cloud blanket and causes increased
precipitation in appropriate areas. In particular, in high latitudes
and altitudes there is increased snowfall or glaciers. [Second] ‘As
the radiation increases still further, the ice melts away and we
have overcast skies and much precipitation but no ice accumulation.’
[Third] ‘When the solar radiation decreases, conditions are reversed
and the whole sequence is gone through in reverse order.’” (After
Simpson, 1938; quotation from Sauer, 1944.)_]

Zeuner has an explanation of why the periodic decrease in the heat from the sun produced glaciation during the last million years and not for 200,000,000 years before. He introduces the geological factor called Eustatism,[15] meaning by it simply a progressive drop in sea level. According to the hypothesis, this began before the Great Ice Age, and was caused by the sinking of very deep portions of the sea floor. As the sea level sank, the temperature of the mountains and plains dropped also, for the higher we rise above the surface of the ocean the cooler the air grows. The snowline fell, the mountain glaciers grew larger, and the snow and ice on the northern plains could not be completely melted by the reduced summer heat, and gradually grew deeper and more extensive. Thus the lowering of general temperature made it possible for the periodic decrease in solar radiation to cause the glaciations of the Great Ice Age. The theory of a general and steady lowering of the sea level is based on a series of four raised beaches occurring uniformly in many parts of the world. Other students believe these terraces were products of a regional rise of land.

Considering that the Great Ice Age ranges back at least 600,000 years—and probably 1,000,000, if we credit evidence of three earlier Danubian glaciations—it is small wonder that scientists are not entirely agreed on many factors in its story. “The difficulties are such,” says the French archaeologist A. Vayson de Pradenne, “that after fifty years of study to which the greatest geologists have devoted all their energies, there is no certainty yet as to the exact number of glaciations and the way in which the faunal changes are related to them.”[16]

Much more important, of course, than the cause of glaciation is its effect on early man. Ice covered 27 per cent of the earth’s surface during the Würm-Wisconsin period, according to Flint. This created the land-bridge over Bering Strait. It connected Santa Rosa Island with the coast of California. It broadened the Isthmus of Panama, so that man did not have to pass through a semi-mountainous jungle, which suggests that he came south during the Wisconsin glaciation. It seems to have been the ice that urged man to the south in the Americas and provided freeways.

5
EARLY MAN IN THE OLD WORLD

_Bone of our bone, and flesh of our flesh, are these half-brutish
prehistoric brothers._
—WILLIAM JAMES

Archaeology, a New Science

Archaeology—digging up the ancient past—is a fairly young science. It is not so young, of course, as electronics or aerodynamics or radiology. It is not so old as astronomy or mathematics or metallurgy. Excavation began in 1748 with the uncovering of Pompeii; but it was hardly scientific, and it reached only a short distance into the past. The deciphering of the Egyptian hieroglyphics in 1819 and of cuneiform writing in 1837 pushed back history two or three thousand years. But deep explorations of man’s prehistoric past won no serious status until the middle of the nineteenth century. “In 1859 prehistoric archaeology,” says Gordon Childe, referring to the acceptance of finds at Abbeville, in France, “may be deemed to have become a science.”[1]

There were discoveries before that, but they were neglected and misinterpreted or despised and disputed. As early as 1690 a man named Conyers discovered “opposite Black Mary’s, near Gray’s Inn Lane,” London, a fossilized tooth which, we now know, belonged to an extinct elephant, and a crude hand ax of stone which, we now recognize, was made by man fairly early in the Great Ice Age; but it was long before they won an honored place in the British Museum. A friend of Conyers named Bagford thought that the elephant belonged to the Roman army of the Emperor Claudius, and that the flint was a weapon used by a Briton to slay it (see illustration below).