266 GLACIAL FORMATIONS OF ERIE AND OHIO BASINS. 



already been noted. Above the upper conglomerate there is, near the 

 headwaters of Middle Creek, a deposit of assorted drift, which, so far as 

 observed by the writer, is uncemented. Since this has not been men- 

 tioned by other writers a brief account of it will be given. By following 

 the road leading south into Middle Creek Valley, past the rock spring, one 

 finds exposed: First, the silt at the 'top of the bluff, which is here about 

 5 feet in thickness; second, a sand of gray color and free from pebbles 

 near top, but becoming brown and pebbly below, and finally grading 

 into a coarse gravel and cobble, the whole formation ha^dng a thickness of 

 about 50 feet. For a vertical distance of perhaps 50 feet below the base 

 of this deposit there are scarcely any signs of drift on the slope, there 

 being outcropping ledges of rock. The upper conglomerate then sets in 

 and occupies a vertical distance of about 100 feet. There are numerous 

 large masses of detached conglomerate, and that which remains attached 

 to the hillside is fissured deeply and presents a very tmeven surface. The 

 rock spring issues from this conglomerate. 



At the base of a large mass of conglomerate near the rock spring an 

 uncemented gravel was found whose pebbles are of medium coarseness. 

 An examination of the pebbles indicates that not more than 1 per cent are 

 of Canadian derivation, the remainder being mainly local limestone. No 

 exposures of the conglomerate were found ou continuing the descent from 

 the rock spring to Middle Ci'eek, the greater part of the slope having out- 

 crops of limestone. The extent of the Middle Creek conglomerate is not 

 known, but it has been observed at intervals for 3 or 4 miles northward 

 from the rock spring. Sutton has traced it to within 2J miles of Split 

 Rock. He has also traced it some distance southward from Middle Creek 

 (see paper cited above). On the farm of W. T. Ryle, about a mile north of 

 the rock spi'ing, there are slight exposures of what may prove to be a drift 

 conglomerate. The outcrop consists of a mass of loosely cemented stones, 

 some of which are angular and others well rounded. They are mainly 

 limestone, but chert pebbles were also observed. No Canadian rocks were 

 found in these beds, but some loose ones occur on the slope near the same 

 horizon, which may have weathered out. Should these outcrops prove to 

 be glacial deposits the conglomerate horizon would be of about the same 

 altitude as the uncemented gravel near the top of the slope above the rock 

 spring. There are on Mr. Ryle's farm, and also on farms east of the rock 



