EMS CLARO eS pea ee 
214 Cincinnati Society of Natural History. 
shores of Owen sound, at 120, 150 and 200 feet above the present level 
of Lake Huron, and some of the higher terraces continue with great 
regularity for several miles. Terraces and ancient beaches are found 
in many places upon Lake Superior. On the north side of the lake, the 
ancient water margins are frequently marked by the wearing of the 
solid rock as well as by the loose materials. In a sandy ridge near the 
western part of Lake Ontario, called Burlington heights, at the height 
of 70 feet above the lake, several bones of the mammoth were discov- 
ered, and in the same excavation, seven feet higher, the horns of the 
wapiti (Cervus canadensis ), and the jaw of a beaver (Castor fiber), were 
also found. 
The drift in Illinois* is divided into-—lIst, blue plastic clay, with 
small pebbles, often containing fragments of wood, and sometimes the 
trunks of trees of considerable size, which form the lower division of 
the mass; 2d, buff and yellow clays and gravel, and irregular beds of 
sand, with bowlders of water-worn rock of various sizes interspersed 
through the whole; and lastly, reddish-brown clays, generally free 
from bowlders, and forming the subsoil in those portions of the State 
remote from the streams, and where the loess is wanting. The 
scratched and grooved surfaces presented by the underlying limestones, 
at many localities, and the smoothly worn and polished surfaces that 
may be seen at others, and the immense size and weight of many of 
the transported bowlders, which have been carried for hundreds of 
miles from the nearest outcrop of the metamorphic beds to which they 
belong, alike preclude the idea that such results have been produced 
by the action of water alone. Huge masses of moving ice, like the 
icebergs of the present day, loaded with the mineral detritus of the far 
northern lands, with angular fragments of hard, metamorphic rock, 
firmly imbedded in the solid ice to act as a graver upon whatever rock 
surface they might come in contact, are the only known agencies that 
seem adequate to the production of the phenomena, characteristic of the 
drift deposits in this State. 
There is an area in the southern part of the State, and another in the 
northwestern part of the State. over which the drift deposits do not 
extend. The lead region of Illinois, Iowa and Wisconsin was not in- 
vaded by the drift, and is, therefore, entirely free from accumulations of 
gravel, pebbles and bowlders, that characterize drift areas, The topo- 
graphical features of the country have been produced by the quiet but 
* Geo. Sur. of Illinois, vol. i. 
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