494 GEOLOGY OF OHIO. 



which are obtainable now, have every appearance of Helderberg, and its 

 presence there argues that under the higher lands between Mad and 

 Miami Rivers that formation still remains, although it was probably 

 eroded in the valley of Mad River by the Drift, and the Niagara exposed. 

 The most northern exposure of the Niagara is at Tremont, in Clarke 

 county, but the conformation of the surface warrants this supposition. 



The gravel in the hills and under the meadows is composed of almost 

 every variety of rock, the limestones largely predominating, but the sur- 

 face bowlders are almost entirely granitic, and have evidently come from 

 a different source and by different means. 



The dividing ridge between Mad and Miami Rivers, in Adams town- 

 ship, and running up to Quincy, in Logan county, is especially well pro- 

 vided with these granitic bowlders, and their angular shapes seem to 

 show that they have been subjected to very little rolling; were wrenched 

 from their places by frost, and transported by ice. 



MATERIAL RESOURCES. 



The one great source of wealth in Champaign county is, and must ever 

 be, her unsurpassed farming lands. Nowhere east of the Prairie State 

 can such broad expanses of meadow be found, and even Illinois can not 

 furnish richer soils, while in the important matter of water-supply few 

 places can compete with her. Her springs and streams are clear and 

 strong, and her wells unfailing. Whether she uses her vast fields for 

 pasture or for tillage, their capacity for producing wealth is unbounded. 

 At present there seems to be a tendency to enlarge farms and devote 

 them to grazing rather than tQ tillage. Whether this is wise and profit- 

 able, is a question for the political economist, and for time. Certainly 

 the fear that many entertain, that this course will diminish population, 

 seems to be justified by facts, the census returns showing that the popu- 

 lation only increased by 1,490 from 1860 to 1870, while in the previous 

 ten years the increase was 2,916, and between 1840 and 1850 the growth 

 was 3,061. 



In stone, the county is not rich, though her wealth in that direction is 

 not fully developed. The Corniferous limestone of the north-eastern 

 townships has scarcely been touched, and very few of the Helderberg 

 quarries have been worked to any extent, and though the quality of 

 stone yet found there is not such as to justify the hope of any extensive 

 commerce, yet there is no doubt that all local demands can easily be met, 

 both for building stone and for lime. 



Of clay, the supply is large and well distributed, and the quality is 

 good enough for brick, drain-tile, and the commoner wares. Probably with 



