24 BIG SPRING PRAIRIE. 



ials of the glacial epoch were deposited in such a man- 

 ner that a lake was formed on the present site of the 

 prairie, a greater deposition of driit occurring at the 

 south end of the valley, and also to the north and west 

 of the prairie area. 



This lake differed but slightly in outline from the 

 present prairie, and it differed considerably in depth. 

 From borings on this area the greatest depth did not 

 much exceed thirty feet and considerable portions were 

 only a few feet in depth, for in some localities the diflf- 

 erence in depth between the surface level and the drift 

 clay or solid rock is quite slight. Bowlders resting on 

 shallow drift clay occur in angle formed by the road- 

 beds of the Hocking Valley R. R. and the Northern 

 Ohio R. R. and just east of this point, in fact just 

 across the tracks, the Niagara limestone lies scarcely 

 two feet below the surface. Bowlders also occur on 

 a rather large area in the vicinity of Springville. 

 Further investigation would be needed to determine 

 whether the preglacial stream flowed northward or 

 southward between the North and West Ridges. 



That this area was a lake in post-glacial times is 

 evidenced by the fact that quicksands, old lake beaches, 

 sand-dunes, etc., exist in various portions. These will 

 be more fully discussed under the various natural areas 

 and plant societies into which the prairie can be divided. 

 When this region was first settled, the natural drainage 

 of the southern portion of the east arm was a broad 

 gradual slope to Spring Run, joining it at the present site 

 of the Gault House, Carey, Ohio. No definite stream 

 existed in this portion within the memory of man; 

 but that such an outlet formerly existed is evidenced 

 by the fact, that the nearly obliterated remains of a 

 beaver dam occurs in the southern portion of this 

 area. It extended in an easterly and westerly dir- 

 ection about half way between Dow street and the 

 Northern Ohio R. R. It filled the gap between the 



