GLACIAL DRIFT IN THE CUYAHOGA VALLEY. 329 



drift; reached 100 feet below that level ; and at the crib, one and a quarter 

 miles offshore, the bottom of the drift was found at the depth of 116 feet, 

 the water of the lake there being 24 feet deep. Throughout the whole 

 tunnel, 65 feet below the lake surface, from the shaft at the shore to the 

 crib, the drift was a compact and very clayey bluish till, containing small 

 rock fragments in abundance, mostly derived from the Erie and Huron 

 shales of the region and of the great lake basin on the north, but holding 

 only very rare boulders so large as one foot in diameter. 



Till having nearly the same characters was also tunneled through dur- 

 ing the summer of this year for laying a large water main beneath the 

 river on Clark avenue, nearly a mile south of the Kingsbury run. 



The axis of the preglacial valley, doubtless 250 feet deep or more at 

 the lake shore, is a mile or more east of the present river's mouth, and 

 the site of the water- works tunnel is on the somewhat gradually ascend- 

 ing slope of the rock westward from the preglacial river bed. Two-thirds 

 of a mile farther west, in Edgewater park, the shale rises above the lake 

 level, and thence forms the precipitous lake shore, 40 to 50 feet high, 

 along the distance of six miles to the preglacial valley of the Rocky 

 river. 



In the east part of Edgewater park the wave-eroded shore cliff consists 

 of till from base to top, about 40 feet above the lake. This till, like that 

 alread}'' described in the two tunnels, has plentiful fragments, up to six 

 inches in diameter, of the Paleozoic shales and of Archean crystalline 

 schists, the latter being derived from Canada by glacial transportation. 

 Boulders of larger size are rare in this deposit. The effect of weathering 

 is seen in the yellowish gray color of the upper 10 feet or more, but the 

 lower part has the same dark bluish color as in the tunnels. In this 

 clearly displayed and freshly undermined shore section an imperfect 

 lamination is plainly observable throughout the upper part of the till to 

 a depth of 15 feet or more, indicating that so much of the gravelly and 

 stony clay, otherwise typical till, was laid down in the waters of the lake 

 when it stood higher than now. To my mind this lamination, which is 

 an almost universal feature of the superficial part of the till in Cleveland 

 up to the highest ancient shore lines, seems to testify that at least the 

 upper 15 to 20 feet of the till belonged to englacial and finally super- 

 glacial drift. If this part had been a subglacial deposit, amassed when 

 the ice-sheet reached its maximum area or at any later time until the 

 recession of the ice border past this vicinity, it could not have received so 

 distinctive lamination, which is evidently due to the presence of water 

 during its deposition, as of the lake held here by the retreating conti- 

 nental glacier. 



This laminated upper portion of the till within the ancient lacustrine 



