Mesozoic and Ctanozoic Geology and Paloiontology. 289 



one ease a continuous furrow was found 100 feet in length. The 

 general direction of these scratches is N.N.E. and S.S.W. though they 

 var}^ a little. One of the remarkable features of the country is a 

 " Lake ridge" passing through the four lake counties nearly parallel to 

 the lake shore, and from four to eight miles distant from the lake. The 

 width of the ridge at the base is from four to eight rods, and narrow- 

 ing toward the top to only two or three rods in width. In many 

 places it much exceeds this width. The elevation of this ridge above 

 lake Ontario is from 160 to 200 feet, though it varies a little from this 

 at some places. The whole of the ridge is superficial, being composed 

 of sand, gravel and pebbles, in all respects similar to those forming 

 the beaches along the present lake shore. South of the ridge there are 

 numerous parallel ridges, composed of sand and gravel, rising about 

 25 to 35 feet above the general level, and ha\'ing uniformly a north and 

 south direction, but never crossing the lake ridge. The opinion ex- 

 pressed in relation to this ridge is that it once constituted part of the 

 shore of the lake, and consequently that the water in the lake was once 

 160 or 200 feet higher than at present, and that the north and south 

 ridges resulted from the overflow of the lake and the pouring out of 

 its waters in a southerly direction. 



Prof. J. W. Foster* separated the surface deposits of Central Ohio 

 into : 1. Vegetable mold; 2. Loam, or a mixture of sand and clay; 

 3, Sand and pebbles; 4. Yellow clay; 5. Dark blue clay effervescing 

 with acids. The whole of which has a thickness of from 50 to 150 feet. 

 And also over the surface of the country there are scattered bowlders 

 of granite, syenite, quartz, etc. In the region about Columbus, some 

 of these erratic blocks contain 1,000 cubic feet. Not even a primitive 

 pebble has been found on the highlands east of Zanesville, showing 

 that the valley of the Muskingum formed a connection of the currents 

 of water, that swept over the country, with the Ohio river. He de- 

 scribed from an excavation for the canal at Nashport, Ohio, Casto- 

 roides ohioensis. It was taken from a laj-^er of dark carbonaceous silt, 

 below a yellowish cla}- bed 14 feet in thickness, but above a laj'er of 

 pebbles of primitive rocks and the blue cla}' at the bottom of the canal. 



Prof. John Locke found the surface of the rocks at Light's quarry 

 seven miles above Dayton, about 448 feet above the Ohio river at Cin- 

 cinnati, planed, scratched and grooved. The quarry had been 

 stripped of soil, more or less, over ten acres. The natural surface of 

 the stone is verj- rough, and in some places this roughness was un- 



Ohio Geo. Rep. 1838. 



