260 GEOLOGY OF OHIO 



ically valuable condition. Even its place is by no means always marked. 

 In numerous sections, distributed through a score of miles at a stretch, 

 its place in the scale will be passed without a blossom of coal, clay, lime- 

 stone or iron ore to indicate the fact. 



Above Steubenville, in the Ohio valley, the I,ower Freeport coal is 

 known as the Roger seam. Many small mines are opened in this seam 

 in Jefferson and Columbiana counties. 



The next best development of the Lower Freeport coal is found 

 along the western margin of the Ohio coal field, from the Hocking valley 

 southward to the valley of the Ohio River. In the Hocking valley it is 

 occasionally fairly developed, attaining a maximum thickness of three 

 feet. The coal is of fair quality, but capricious in its development to a 

 high degree. 



The reference of what is known as the Hamden Furnace coal to the 

 Lower Freeport horizon, which was made in Volume V, has been proved 

 to be erroneous, by the work done in the present report. The seam thus 

 designated has been shown to be the Middle Kittanning coal by means 

 of a better series of sections than was before found. * 



In Lawrence county the Lower Freeport coal is known as the 

 Hatcher vein. It is about three feet thick at its best and at present ren- 

 ders a small measure of service in supporting small mines for neighbor- 

 hood supply. 



The Steubenville coal lies entirely below drainage, but an exception 

 has been made for this important field by indicating it on map No. 8, 

 covering the territory in which it is now being mined. As a rule no ac- 

 count has been taken of coal seams when they have fallen below 

 drainage. 



In regard to the Steubenville coal a question of identification has 

 always existed. Dr. Newberry referred it confidently to the Upper Free- 

 port horizon, and he had the analogies of this seam in his favor in this 

 reference. More careful work, however, done in the preparation of 

 Volume V, seemed to necessitate its reference to the Lower Freeport hori- 

 zon. While it has all along been acknowledged that the horizon of this 

 field is not as definitely settled as those of our other coal fields may be 

 said to be, nothing has come to light that tends to really unsettle this 

 conclusion. In the preparation of the present volume, a review of the 

 Steubenville field, with special reference to this question, has been made 

 by Prof. F. W. Sperr, who did the work of determination for Vol. V. but 

 no change has been warranted thereby. The main facts that tend to 

 keep the question open are those derived from the drilling of deep wells 

 in the territory contiguous to western Jefferson count}*. The Cambridge 

 coal (Upper Freeport) is found running down under deep cover towards 

 the known extension of the Steubenville seam. 



The most that can now be said is, that the facts gathered from the 



* This new determination is to be credited to Mr. C. E. Sherman, an assistant 

 on the Survey for 1892-3. 



