48 THE PREGLACIAL DRAINAGE OF OHIO. 



includes the Savannah Lakes in Ashland county. It forms the 

 rim of a bowl or hydrographic basin, and its pinnacles of highest 

 hills show as the zig-zag wanderings of a worm fence. 



The rivulets and creeks dovetail and intertwine like the 

 locking of lingers ; while all along the crest are to be found, 

 between the exposures of native rock, the remains of old lakes, 

 gravel knolls, cat swamps, sink holes, and millions of boulders, 

 the largest two lying near Lodi and Ashland, with an estimated 

 weight of 300 and 350 tons respectively. 



The elevations of this rim above Lake Erie are, Wadsworth 

 700 feet. But Wadsworth is underlaid with coal, and is there- 

 fore east of our pre-glacial channel, which must run exactly be- 

 fzcccii the Coal Measure hills and the Waverly capped Island. 



Seville is on carboniferous conglomerate, and is situated 

 west of the valley of the river Styx, which drains the coal fields 

 north and west of Wadsworth. It is just on the edge of the Coal 

 Measures, and its elevation is 403 feet above Lake Erie, while 

 drillings in the vicinity show 300 feet of drift. This makes a 

 rapid decline of near 600 feet in six miles to the rock bottom 

 of the Seville valley, and the surface decline continues west into 

 a broad valley, where we are justified in assuming the same 

 amount of drift with a lower well head, although no drillings have 

 been made in the center of the valley. 



On the west side of this valley i| miles east of Leroy, and 

 southwest of Chippewa Lake, a drilled well shows 149 feet to 

 rock, and going north east to a point 4^ miles due south of Me- 

 dina village, and northeast of Chippewa Lake, a drill was sunk 

 190 feet and no rock was struck, but ^ miles north, Waverly rock 

 was struck at 125 feet. While i^ miles south, rock was struck 

 in Carboniferous conglomerate at 42 feet, showing a north- 

 east channel through Chippewa Lake on the edge of the con- 

 glomerate. 



Following this line to a well three miles due east of Medina, 

 near the head of Rocky river, I find 140 feet of blue clay above 

 6g feet of white sand; the well was abandoned at 200 feet without 

 reaching rock, as sand ran up the pipe to water level. This well 

 head is 180 feet below Medina and it makes the bottom of this 

 drill hole 133 feet above Lake Erie. 



