10 PROCEEDINGS OF THE BUFFALO MEETING. 



greatest depth of the preglacial valley is found atGiddings avenue, about two miles 

 from the eastern bluff. The depth to the bed rock there is 440 feet, reaching 340 

 feet below the level of lake Erie. From the top of the bluff at the Garfield monu- 

 ment to the bottom of the ancient gorge is a vertical depth of 590 feet. Within a 

 half mile east from Giddings avenue, the side of the gorge, under the drift, has an 

 ascent of 315 feet. The western side has a more gentle slope, rising 115 feet in 

 about a half mile, and thence rising about 120 feet in the next two miles to the 

 Public square. Thence the old valley bed is nearly level for more than a mile, to 

 the vicinity of the water works ; but farther west it rises about 100 feet in little 

 more than a half mile and continues to rise more slowly to the western city limits. 



It is probable, however, that this section, as revealed by the wells recorded, fails 

 to reach the deepest point of the old valley. Another well on Giddings avenue, 

 near Lawnview and Astor avenues, about half a mile north of Euclid avenue and on 

 land about 15 feet lower, has the depth of 475 feet to the bed rock, which is reached 

 thus about 50 feet lower than near the intersection of Euclid and Giddings avenues. 



South of the Euclid avenue section, a well near the intersection of Woodland 

 avenue and Jackson street, a mile southwest of the Case avenue well in the fore- 

 going list, reached the bed rock at 320 feet. It is on ground about 105 feet above 

 the mean lake level. 



There remains to be noted only one other well, but this shows the greatest depth 

 of drift yet found, and it is the most northern and nearest to the lake shore, being 

 situated near the junction of Bratenahl street and Girard avenue, on the east line 

 of Gordon park. This well was bored, according to Mr Duff (in company with Mi- 

 Gilbert), to a depth of 520 feet, and was then abandoned without reaching the base 

 of the drift. The ground there is about 50 feet above the lake, which is a third of 

 a mile distant on the north. The bottom of the preglacial valley near its place of 

 passing out beneath the lake is thus at least 470 feet below the lake level. 



Inspecting these records, we find that, within the area of the city of Cleveland, 

 the line of maximum depth of the old valley lies near its eastern side and runs 

 north-northeastward, passing near the Forest City park, the intersection of Gid- 

 dings and Euclid avenues, and Gordon park. Where the preglacial 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 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 340 feet ; a half mile farther north it is 390 feet, if not 

 more ; and at Gordon park it is known to exceed 470 feet. 



Because of the greater expense of boring in the drift than in the underlying 

 shales, the base of the drift has been carefully determined; but the succession of 

 diverse drift deposits, and their respective thicknesses, have not been so noted. Con- 

 cerning the characters of the drift, Mr Gilbert informs me that, beneath the super- 

 ficial Cuyahoga delta sand and gravel, usually 10 to 20 feet deep, as described in 

 my former paper, a considerable thickness of stony and gravelly clay or till is 

 passed through, with occasional enclosed beds of stratified gravel and sand ; but 

 that the lower portion of some of the very deep drift sections consists chiefly of 

 sand and gravel, resembling those of the present lake beaches. In the till of the 

 well at the Public square he bored through a log fully two feet in diameter, thought 

 to be oak, at the depth of 1 25 feet. In this well a stratum of seven feet of very 

 fine quicksand lay immediately upon the shale ; but in some other deep wells the 

 lowest drift deposit is clay, probably till. 



