56 HISTORY OF OHIO. 



highest lands in the state, are along these summits and on the 

 summits between the valleys of the largest rivers— such as 

 the Muskingum, and the Scioto— the latter, and the Little 

 Miami rirer. Jackson, Highland, Lawrence and Guernsey 

 counties contain as highly elevated grounds as any in the 

 state. The high grounds, on the summits near lake Erie, are 

 swampy and wet; but, in the counties lying in ihe southern 

 parts of the state, the summits are dry, mountainous, or hilly 



tracts. 



The swampy lands in the state, (excepting those near lake 

 Eric, over which, the lake flows so as to drown them) are, 

 mostly underlaid, with blue clay, of such a thickness and 

 compactness, as to prevent the water's descent below it. We 

 except, too, the swampy grounds along the rivers, which are 

 too low to be drained.. 



ALLUVIAL DEPOSITES. 



Those beds of clay, sand, gravel and pebbles which consti- 

 tute so large a portion of the earth's surface along all our riv- 

 ers, which fall into the Ohio river, are called alluvial depo- 

 sites. These substances, which have been disintegrated, by 

 the action of the atmosphere, frost and water, have been 

 transported subsequently by the rivers, and deposited in hori- 

 zontal beds, in valleys, in the beds of streams, or in plains. 



These deposites are of a comparatively recent date. Some 

 of them have been deposited within our own memory and others 

 are now forming, under our own observation. They are pe- 

 culiarly interesting, indicating important changes in the earth's 

 sirrface; and the examination of these deposites, is important 

 to many classes of men; — to the farmer, miner and manufact- 

 urer. Their contents are sometimes very valuable, because 

 they often contain beds of clay, which are useful to the brick- 

 maker, the potter and the clothier. Besides peat, they often 

 contain bog-iron ore, and calcareous tufa. 



Besides trees, the remains of extinct animals are sometimes 

 found in these deposites. Numerous organic remains, the 



