QUATERNARY AND RECENT. 
305 
Epochs. 
Earlier Glacial 
Epoch. 
Chief Interglacial 
Epoch. 
Later Glacial 
Epoch. 
Cliam plain 
Epoch. 
Terrace Epoch. . 
Sub-Epochs or 
Episodes. 
f First sub-epoch, 
Interglacial, . 
[ Second sub-epoch, 
First episode, . 
Deglaciation, . 
Second episode, 
Deglaciation, . 
Third episode, 
i Later stages, . 
Attendant or Characteristic 
Phenomena. 
Drift-sheet, with attenuated 
border, scanty marginal 
drainage. 
Ferruginated, etc. 
Loess. 
Elevation of Upper Mississippi 
region, zfc 1000 ieet. 
Till-sheot, bordered by Kettle 
Moraine. 
Vegetal deposits. 
Till-sheet, bordered by the 
Gary Moraine. 
Till, bordered by the Antelope 
Moraine. 
Marked by terminal moraines. 
Marine Champlain, lacustrine 
deposits about Great Lakes. 
Fluvial excavation of flood 
j'lains of second glacial 
epoch. ■. 
The glacial lakes Agasbiz, Bonneville and Lahontan are noticed 
elsewhere, also the region of the great lakes. On the Pacific 
coast the Plistocene marine beds have about the same bulk as 
those on the Atlantic. There are, besides, immense lacustrine beds 
in the valleys of the Sacramento, San Joaquin, Willamette, etc. 
Possibly the sands and gravels may be thousands of feet thick in 
some of the valleys. The auriferous fluviatile deposits on the 
slopes of the Sierra Nevada are regarded as Pliocene by J. D. 
Whitney. The evidence of feeble glacial action in the Sierras 
has been described, and the glaciers .still remain. 
The flood plains of the river valleys, out of which terraces 
have been carved, are composed of material derived from the till 
and deposited rapidly in water swollen to enormous volume by 
the melting of the ice 
Towards the mouths of the rivers they 
may merge into marine deposits after reaching the level of tide 
water. Elevated beaches cannot be regarded as oceanic in the 
absence of marine fossils. 
