224 
The American Geologist. 
Octolx^r, IMtfi 
depth of drift revealed a very interesting- preglaeial valley and different 
conditions of topography and drainage from those of the present day; 
for the greater part of lake Erie, as is well known, is only about 80 feet 
deep, while its maximum dejith, api^irently in an old river valley now 
covered by the lake, is only 210 feet. It was also ascertained by New- 
berry, from borings for oil, that where the Cuyahoga river enters Cuya- 
hoga county, about thirteen miles fi'om the lake Erie shore at Cleveland, 
the bottom of the i)reglacial gorge is 220 feet below the present river, 
or about 175 feet below the level of the lake. 
By inspecting the additional well records, it is found that, within the 
area of the city of Cleveland, shown in figure 1, the line of maximum 
Fig. 1. Map OF THE City of Cleveland, showing its areas of glacial and 
VALLEY DRIFT. (Reduced from a islate in the Bulletin of the Geol. Soc. of America, 
vol. VII.) 
depth of the old valley lies near its east side and runs toward the north- 
northeast, passing near to the Forest City park, the intersection of 
Giddings and Euclid avenues, and Gordon park. Where the preglaeial 
Cuyahoga gorge enters this county, it had already attained a depth of 
175 feet below the present lake; in the northern edge of Independence 
township, eight miles from the lake, its depth below the same plane is 
333 feet, without there reaching the bed rock; at Giddings and Euclid 
avenues, its depth is at least 310 feet; a half mile farther north, it is .390 
feet, if not more; and at Gordon park it is known to exceed 470 feet.— 
all being depths below lake Erie. 
Because of the greater expense of boring in the drift than in the un- 
derlying shale, the depth to the base of the drift has been carefully de- 
termined: but the succession of diverse drift deposits, and their respec- 
tive thicknesses, have not been so noted. Concerning the characters of 
the drift, Mr. Gilbert states that, beneath the superficial Cuyahoga 
