STRATIGRAPHIC SUMMARY. 663 



York, Ontario and Quebec, in New England, and in New Bruns- 

 wick. They are sometimes divided into Leda clays below and 

 Saxicava sands above. The Sankaty Head beds of Nantucket are 

 regarded by Wilson as pre- Wisconsin in age. 



The San Pedro beds of California and the Admiralty beds 

 (below) and the Vashon beds (above) of western Wasington 

 represent other marine Pleistocenic deposits. The Toronto inter- 

 glacial beds of pre- Wisconsin age are famous for their insect and 

 molluscan faunas and their plants. The lower part of the series 

 constitutes the Don formation with a warm-temperate fauna and 

 flora, and the upper part the Scarboro formation with a cold- 

 temperate flora and fauna, the latter including y2 species of beetles. 



On the Atlantic coast, the Columbia formation represents a 

 fluviatile deposit outside of the glaciated area. It is subdivided in 

 ascending order into the Bridgeton formation, Pensauken formation 

 and Cape May formation. The two higher formations occasionally 

 contain marine fossils. The Sheridan or Equus beds of the Great 

 Plains region are western non-marine Pleistocenic. 



The Prairie Loess, west of the Mississippi River, is believed to 

 be mostly of the age of the lUinoisan drift sheet; but somewhat 

 earlier and later deposits of Loess also occur. Its fauna is ter- 

 restrial and fresh water. 



Pleistocenic deposits of lacustrine origin are found in Lake 

 Bonneville and Lake Lahonton, and of the Glacio-lacustrine stage 

 in Lake Agassiz and other glacial lakes. Here also belong the 

 fossiliferous high beaches of the Great Lakes and the Shell gravels 

 of Goat Island in Niagara River. 



XVII. The Holocenic or Recent System. 

 The modern deposits off the coast of North America are for 

 the most part still submerged. From dredgings, however, these 

 deposits often become accessible and are then found to be crowded 

 with the shells of still living species of moUusks, etc. Raised coral 

 reefs, such as those on Cuba and Florida, show modern species of 

 corals, and the shell limestones (Coquina) of Florida and else- 

 where are of living species. Modern continental deposits — fluvia- 

 tile, eolian, lacustrine, etc., preserve remnants of the living fauna. 

 The Kitchenmidden deposits of New England, New York, the 

 California coast, etc., are rich in shells of living species of molluscs. 



