36 BULLETIN OF THE LABORATORIES 



Toboso. At the winter meeting of the Ohio State Academy of 

 Science the outHne of part of this paper was presented and cer- 

 tain conclusions were suggested. Since that meeting many 

 new facts have been collected which have considerably modified 

 the conclusions there presented. The facts given at that time 

 have been carefully re-established. The order of presentation 

 is that followed in the field work and investigations. The prin- 

 cipal lines of evidence employed may be grouped under two 

 heads — Topographical and Structural. 



Under the topographical is included the present surface 

 topography, its particular form and elevation ; the topography 

 of the rock surface as indicated by exposures and well borings. 

 Under the structural is included the geological formation of the 

 rock and the character of the glacial drift. 



2. Topography and Present Drainage of Licking County. 



Licking county lies near the centre of Ohio and its present 

 drainage is by the Licking river, which is formed at Newark by 

 the confluence of three streams, the North and South Forks and 

 Raccoon creek. These streams form a hydrographical basin 

 which is very nearly co-extensive with the county lines. Rac- 

 coon creek and the larger tributaries of North Fork rise in 

 the northwestern portion which is a rather high, undulating ta- 

 ble land, 1 3 14 feet A. T. They flow through rather broad and 

 open valleys ranging from one half to one mile in width between 

 the Waverly hills. The valleys are filled with drift to a depth 

 of 100 to 150 feet, increasing in depth as we pass down stream 

 until at Newark the gas well borings show a valley filling of 

 over 300 feet, making the rock floor of the old valley about 500 

 feet A. T. 



These two streams are of rapid fall, descending 350 to 400 

 feet in the 40 to 50 miles of their lengths. The South Fork 

 rises on high ground in the southwestern portion of the county, 

 flows south and east to near the Licking Reservoir, which lies 

 about 125 feet above Newark, or 944 feet A. T. From this 



