240 THE POPULAR SCIENCE MONTHLY. 



shown in the numerous excavations made for building purposes about 

 Brooklyn. The bowlders upon Long Island have all been brought 

 from the northwest, and those familiar with the ledges in Connecticut 

 and up the Hudson can readily recognize the fragments in the vari- 

 ous parts of the island the Palisade traps in Brooklyn, and the New 

 Haven red sandstones to the southeast of their place upon the main- 

 land. 



We can recognize the inner moraine in Ohio, while its remnants 

 may be found in New York State by future investigators. Dr. New- 

 berry describes a line of kames occupying the water-shed between 

 the affluents of the Ohio and Lake Erie, which can be easily correlated 

 with the modified drift fringing our terminal moraine. This line ex- 

 tends entirely through Ohio, and bends sharply at Fort Wayne, Indi- 

 ana, following St. Joseph's River northeasterly, so that its whole course 

 is parallel to the shore of Lake Erie. N. II. Winched thinks there 

 are several of these moraines in the northwest part of Ohio. Professor 

 T. C. Chamberlin has generalized the facts about the course of these 

 moraines between Pennsylvania and Minnesota, and supposes there 

 are two morainic lines parallel to the shore of Lake Erie, the outer 

 reaching to middle Indiana. Likewise there appear moraines in the 

 form of loops following the course of the shores of Lake Michigan, 

 Green Bay, Keweenaw Bay, and the southwest end of Lake Superior. 

 The glaciers seem to have followed the several valleys, continuing to 

 flow as long as the material lasted. The Green Bay and Lake Supe- 

 rior streams did not cover the area in the lee of the highlands of 

 northern Wisconsin ; and hence there was a large tract of land, occu- 

 pying essentially what is known as the "Lead-region of the North- 

 west," over which we search in vain for erratics or glaciated surfaces. 

 Mr. Warren Upham has communicated to us many facts for Minne- 

 sota, Dakota, and Iowa. They indicate two looped moraines west of 

 the Mississippi : one reaching nearly to Yankton, Dakota, having the 

 celebrated Coteau de Missouri for its western border, and part of the 

 Coteau de Prairie for its eastern ; the other taking the eastern line of 

 the Coteau de Prairie for one side, and pointing east of south to Des 

 Moines, Iowa. An inner loop connecting the Wisconsin moraine with 

 that of the Leaf Hills may have been pushed there by the Lake Su- 

 perior stream, and the more southern loops may have had some con- 

 nection with glaciers starting in the Dominion portions of the Rocky 

 Mountains. I [ence the Labrador and Rocky Mountain sheets may have 

 been confluent, and, owing to the great masses of ice thus accumulated 

 along the upper part of the tributaries of the Mississippi basin, we 

 may understand why the glacier extended so much farther south in 

 the interior than upon either coast. 



Elevation of the Land in the Glacial Age. The earlier 

 writers accounted for the glacial cold by supposing the land had been 

 elevated sufficiently to lower the temperature, and subsequently de- 



