i8o The Americmi Geologist. March, i899 
sixty feet near the Shelby county H'nes to twenty-five feet just 
east of the city, St. Marys. The five wells, sunk in as many 
miles, and all showing the same depth, suggest that this is 
the normal depth of the channel. 
St. Marys at the canal is 814 feet above the sea level. The 
country to the southeast along the channel is quite level, and 
hence varies little in altitude from St. Marys. Taking 370 
feet as the normal depth of the channel, it follows that the 
bed of the channel is 494 feet above sea level. The surface of 
lake Erie is 573 feet above tide; hence the channel is seventy- 
nine feet below the surface of lake Erie. Possibly the normal 
depth of the channel may be greater than 370 feet, and if so the 
depth of the channel below the surface of the lake is greater 
than the figure above given. 
Continuing w'est from St. Marys the channel passes di- 
rectly through Grand reservoir, but a little distance north 
of the middle line. Numerous walls here show depths rang- 
ing from 360 feet to 380 feet, while along the shores the drift 
varies from forty-five to one hundred feet. Ne?r the west 
end of the reservoir the channel turns abruptly tc the north, 
and between this point and Rockford depths of 403, 340, 300, 
400, 400, 225, and 350 feet were found in successive wells. 
The deepest wells in this territory show that the old river 
had cut entirely through the limestones and was eroding the 
shales below. The drift on each side of the channel between 
the reservoir and Rockford is shallow, varying from sixty to 
eighty feet. Running due west from Rockford the channel 
can be followed, though the oil men have not invaded this 
territory. Water wells show depths of drift of 100 feet with- 
out reaching rock, while north and south of this line depths are 
notably smaller. 
Passing into Adams county, Indiana, the same conditions 
prevail. Water wells show depths of 150 feet without reach- 
ing the rock, while north or south of this line the drift is 
less than one hundred feet deep. Soon after entering Indiana 
the channel bends to the southwest passing beneath the town 
(ieneva where about four hundred feet of drift are found. 
Less than three miles west of this town one well disclosed 
only twenty feet of drift. From Geneva the channel continues 
in a curve, extending across the northwest corner of Jay coun- 
