CHAMPAISN COUNTY. 493 



in the bottoms, the gravel is buried deep, under alluvium and peaty 

 matter. 



Every township has beds of clay, valuable for brick and tile-making ; 

 and considerable quantities of those articles are made for local use. 



Tile-works are in operation at several points — as Woodstock, St. Paris, 

 and Addison. 



On the higher lands, sugar, and beech trees flourish well, while the 

 central part is more occupied by oak and hickory. Elm, poplar, and 

 many other kinds, exist in considerable numbers, but the four genera 

 mentioned, give character to the forest, and are typical of it. 



In the north-western townships, there were, until lately, large num- 

 bers of poplar trees (Liriodendron), but they have now been almost exter- 

 minated. 



In the south-eastern part of Mad River township is a large tract known 

 as "Cedar Swamp," from the fine growth of white cedar, or arbor vitee, 

 covering it. Being too wet for the pasturage of either swine or cattle, 

 its peculiar flora throve unmolested, and made the place a favorite resort 

 for botanists. But the cedars are being rapidly felled, and the swamp 

 drained, and in a few years will disappear entirely. 



The white cedar (Thuja occidentalis) of the swamps, and the red cedar 

 (Juniperus Virginiana) of the hills, are the only conifers native to the 

 county. 



GEOLOGICAL STRUCTUEE. 



The Drift overlies the whole county, excepting those low lands where 

 its own waste and the swamp growth have covered it with alluvial soil. 

 The highest rock formation, only seen in small parts of two townships, 

 the north-east corner of Salem and the north-west corner of Wayne, is 

 the Huron shale or black slate. The larger shale island of Logan county 

 sends this spur down into Champaign. Under the shale the Corniferous 

 limestone is exposed in a few places in the same townships, and though 

 it has only been quarried in a very small way, for local purposes, it 

 would doubtless prove valuable if more thoroughly worked. 



Southward and westward the Helderberg, or water-lime rock, has been 

 opened in numerous places, though but one quarry, Mr. McCoursey's, in 

 section 2, Salem township, is now worked to any extent. It was from 

 this quarry that most of the building-stone of Urbana was taken, and 

 much of it was used for flagging, until the better stone of Berea super- 

 seded it. The numerous "sun cracks" in the ChaHlpaign county atbne 

 interfere with its use as flagging. 



The only quarry west of Mad River is in the center of Jackson town- 

 ship, but it has not been worked for years. The fragments of thie &ck 



