210 J. W. Spencer — High Level Shores of the 



often covered in part with gravel floors, and in part with. 

 silt. They are the exact counterpart of the plains in front 

 of the lower beaches, although more eroded by the streams 

 cutting down to the lower levels. Thus extending from the 

 vicinity of Kalamazoo there is an extensive plain, with a floor 

 of well-rounded gravel, bounded on the south by ridges but 

 with a generally open and descending country to the north. 

 On this plain, I have traveled for forty miles to eastward of 

 Marshall, and could see in it no other history than that of 

 the bottom of some bay in front of ridges of drift hills 

 towards the south. The barometric height taken from the 

 station at Kalamazoo gives the plain or terrace an elevation of 

 912 feet above the sea. Farther eastward the measurements 

 reached 944 feet. In the valleys, there are lower river ter- 

 races probably corresponding to the Maumee Beach. The 

 amount of warping in the region is very little. It has also 

 been noted that there is scarcely any deformation south of 

 Lake Erie until passing eastward of Madison, Ohio. It is well 

 known that there are at last four troughs in Ohio connecting 

 the Erie valley with that of the Ohio Eiver having summit 

 floors at elevations of between 909 and 940 feet above the 

 sea, composed of drift materials, and that there are terraces 

 at the northern end of these valleys.* The terraces at the head 

 of the Mahoning valley is a good example. It is probable that 

 the gravel plains of Michigan and the terraces in Ohio, con- 

 nected with these meridional troughs, are identical in age. 

 But here is room for investigation. In Michigan, there are 

 other and higher gravel flats than those just referred to. 



Professer Pominger records beach-like deposits at 1,682 

 feet above the sea on the highest lands near the northern 

 part of the lower peninsula of Michigan. f Professor E. Desor 

 noticed other similar deposits at considerable elevations in the 

 northern peninsula of that State. J Mr. A. Murray long ago re- 

 ported a series of beaches on the northern side of Lake Supe- 

 rior.! Professor H. Y. Hind observed terraces at Great Dog 

 Portage, north of the same lake at 1,435 feet.J Other beaches 

 at 1,100 feet have been reported in Wisconsin. J^one of these 

 I have seen, and do not know which of them, except those 

 north of Superior, belong to true beaches, for I have every- 

 where had to distinguish between plain shore structures and 

 those forms which go under the name of kames, osar, etc. 



* Geology of Ohio, vol. ii, p. 47. 

 f Geology of Michigan, vol. hi, p. 10. 



\ See Beaches, etc., between Lakes Mich, and Sup., by E. Desor in Foster and 

 Whitney's Report, vol. ii. 



§ Geology of Canada for 1863. 



|| Report upon Assiniboine and Saskatchewan Expedition, 1859, p. 120. 



