MORROW COUNTY. 265 



county line. The excavation by the creek is, on an average, about 

 twenty-five feet in the slate. Many of the little ravines joining the 

 creek show it in their banks. In the south-western part of the township 

 of Peru are what are known as " slate knobs " along the Olentangy, 

 which have a sparseness of soil and too easy drainage, making them poor 

 for agriculture. 



At Westfield the black slate is exposed in the banks of the East Branch 

 of the Olentangy, on the land of J. B. Trindle. It was also struck in 

 digging for the foundations for the flouring mill half a mile below West- 

 field. 



The Drift. — The whole county is heavily covered with northern Drift. 

 It embraces stones of all sizes, irregular patches of stratified gravel and 

 sand, and much clay. The mass of the whole is made up of that usually 

 denominated "blue clay," although the blue color is only found at the 

 depth of fifteen or twenty feet, the action of the air and water on the 

 iron and other substances contained in it having produced hydrated, im- 

 pure peroxides that pervade the soils and the clay to about that depth. 

 The Drift is usually perfectly unassorted; yet at Mt. Gilead, where there 

 seems to have been an accumulation of standing water about the foot of 

 the glacier, the upper portion of the Drift clay is very fine, and free from 

 stones and gravel. This clay here also shows the exceptional character 

 of stratification, although the lamina? are considerably disturbed, not 

 lying so true and nearly horizontal as in the laminated clays at Fremont 

 or at Cleveland. The average thickness of the Drift would probably not 

 exceed forty feet. It seems to be thicker in the northern part of the 

 county than in the southern. 



About a mile above Mt. Gilead the left bank of the East Branch of the 

 Olentangy consists, so far as seen, of hard-pan, containing bowlders 

 throughout from top to bottom, and measures sixty-four feet nine inches. 

 This was a fresh exposure, where the washing over the dam had laid it 

 bare. Only ten feet of the blue hard-pan can be seen, the lower portion 

 being hid by debris. The thickness of the oxidated Drift was about 

 eighteen feet. One very large northern bowlder was seen projecting 

 from the bank, just above the lowest part of the brown harJ-pan. Half 

 a mile below Westfield the banks of the same creek show thirty-one feet 

 seven inches of Drift, made up according to the following section, in 

 descending order : 



Section of the Drift near Westfield, Morrow County. 



No. 1. Hard-pan (unstratified) 21 ft. 



" 2. Gravel (stratified) 10 " 7 in. 



Total thickness 31ft. 7 in. 



