Chapter XVII

FORMER GLACIAL EPOCHS.—REASON OF THE IMPERFECTION OF
GEOLOGICAL RECORDS IN REFERENCE TO THEM.

Two Reasons why so little is known of Glacial Epochs.—Evidence
of Glaciation to be found on Land-surfaces.—Where are all
our ancient Land-surfaces?—The stratified Rocks consist
of a Series of old Sea-bottoms.—Transformation of a
Land-surface into a Sea-bottom obliterates all Traces of
Glaciation.—Why so little remains of the Boulder Clays of
former Glacial Epochs.—Records of the Glacial Epoch are fast
disappearing.—Icebergs do not striate the Sea-bottom.—Mr.
Campbell’s Observations on the Coast of Labrador.—Amount
of Material transported by Icebergs much exaggerated.—Mr.
Packard on the Glacial Phenomena of Labrador.—Boulder Clay
the Product of Land-ice.—Palæontological Evidence.—Paucity of
Life characteristic of a Glacial Period.—Warm Periods better
represented by Organic Remains than cold.—Why the Climate
of the Tertiary Period was supposed to be warmer than the
present.—Mr. James Geikie on the Defects of Palæontological
Evidence.—Conclusion 266