170 GEOLOGY OF OHIO. 
to me incompatible with the view to which I have referred. So much as 
this seems to be required of me; as, if this view were accepted, it would 
destroy all confidence in the classification of our coal seams which I have 
adopted, and if true, a large part of what I have written on this subject 
is necessarily false. For the proof of the general truth of the order of 
sequence which I have reported as prevailing over most of Ohio, I must 
appeal to the series of sections published on the sheets that accompany 
this report, and to the several experienced geologists who have carefully 
gone over the ground where these sections were taken. Some of the spe- 
cific facts which seem to me to be incompatible with the theory of the 
inflexible parallelism of coal seams I give below. 
In tracing the outcrop of Coal No. 1 throughout all the counties where 
it is worked in northern Ohio, I have found this seam to be exceedingly 
variable in its level. It often shows a series of waves, or folds, in which 
the arches are sometimes as much as 50 feet higher than the basins, 
within the limits of a few hundred acres. This irregularity is well 
shown in a large number of mines that are opened in this coal in Trum- 
bull, Mahoning, and Stark counties. Perhaps no better illustration of it 
could be offered than that described by Mr. Read in his report on Trum- 
bull county (Vol. I., Part I., p. 498); since he there shows that on a tract 
of land held by one company the variation in the distance between coal 
seams No. 1 and No. 2 amounts to more than 50 feet. In this case there 
can certainly be no question in regard to the identity of the two seams 
passed through. 
A similar variation in the interval between Coals No. 3 and No. 4 is 
revealed.in the shaft and borings, thirteen in number, made on the prop- 
erty of Tod, Stambaugh «& Co., in the north-west corner of Carroll county. 
Here, within an area of which the diameter is 1200 feet, the distance 
between these coals varies from 20 to 45 feet. Here, also, there can be 
no question of identity, as each of the coal seams is marked by its over- 
lying limestone, and both are well known throughout all this section of 
the State. I have myself traced these coals (Nos. 8 and 4) over more 
than two hundred miles of outcrop, and have taken sections which include 
them in many hundreds of localities. Within the range of my own ob- 
servation I have known the interval between them to vary from 20 to 90 
feet, and Prof. Stevenson reports them to be even 110 feet apart in one 
locality in north-western Guernsey county. 
The interval between Coals No. 4 and No. 6 exhibits nearly as great a 
variation as that between Coals No. 3 and No. 4. The horizon of Coal 
No. 4 is one of the most distinctly marked of any in the Coal Measures, 
