320 



COAL FIELDS OF OHIO. 



The geological structure of this coal-field is very- 

 similar to those already described. Some parts of 

 the valley belong to the tertiary, some to the car- 

 boniferous, and some to the red sandstone group. 

 The remains of fossil plants are very numerous and 

 beautiful, and the beds of red marl are of immense 

 thickness, often as much as 40 feet, which, on ex- 

 posure to the air and frosts, decompose into a red 

 clay highly charged with iron, and disclosing nod- 

 ules of red oxide of iron in considerable quantities, 

 and shells of the genus unto, which shows that the 

 deposites were made in fresh water. In boring for 

 salt water six miles above the mouth of the Mus- 

 kingum in 1834, after passing through 40 feet of 

 clay, they came upon a softer clay, mixed with sand 

 and small fragments of wood, leaves, and seeds of 

 monocotyledinous plants ; and under this a bed of 

 woody materials, composed of the fragments of 

 trunks and branches of trees, grapevines, seeds, 

 and leaves. Under this was a deposite of 10 feet 

 of fine sand mixed with clay, precisely such as we 

 find in the beds of our ponds, and mixed with nu- 

 merous fresh- water shells. The reader may learn 

 the nature of the strata of the coal-fields of Ohio by 

 recurring to the sections given in our chapter on the 

 coal measures. An excellent species of coal, simi- 

 lar to that of the Cumberland beds, and called by 

 some Cannel coal, has been discovered on Will's 

 Creek, in Guernsey county, of which an account is 

 published in the 18th volume of Silliman's Journal. 



Hocking Valley Coal-field. — The Hocking River is 

 about 80 miles long, and, with its tributary streams, 

 drains a valley about 20 miles in width. * The val- 

 ley is generally hilly and broken, the hills rising 

 from 200 to 300 feet high. In the centre of this 

 valley bituminous coal is found in abundance, and 

 with its associated minerals, iron and salt, will soon 

 be extensive and lucrative articles of commerce. 

 It is found in three principal beds, pursuing the 



