104. : GEOLOGY OF OHIO. 
constantly varying, and can be determined only by careful observation 
in each locality; and that any general statements that suggest the in- 
ference that there is a uniform dip in any particular direction, are cal- 
culated to mislead. In the mine at Haydenville, where now worked, the 
dip is one foot in thirty-five, or over 150 feet per mile: and observation 
shows that the local dip may be in any direction, and that it constantly 
varies in amount within very wide limits. Observations and calcula- 
tions made on widely separated data at different points will show the 
general dip of the rock strata. After all, these irregularities and undu- 
lations are eliminated or disregarded, but they are calculated to mislead 
the practical miners, unless supplemented by minute and detailed work 
in each locality, requiring more work than can ordinarily be given to a 
State survey. 
The relation of the seam to the other mineral deposits is illustrated in 
the section here given: 
