404 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 to 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 seat is 
good enough for brick, drain-tile, and the commoner wares. Probably with 
