Coal Strata. — Kenaivha VaUey. 



109 



Neuropteris — some of the leaves are replaced by oclire and others 

 by bituminous matter. The two latter figures were drawn by Mrs. 

 Bridiam of Charleston, Va- 



bed 



It contains 



rather more carbonaceous matter than the lower bod, seventeen and 

 a half grains of it decomposing one bunded grains of the nitrate of 

 potash, which will give it about sixty five per cent of charcoal. For- 

 ty grains burned in a crucible and kept for a few minutes, at a red 

 heat, left twenty four grains of coak, — Coal. — 4 feet. 



7. Coarse, sharp grained, silicious, sandstone. This deposit 

 reposes immediately on the coal without any intervening slate, or 

 shale, and forms a very safe and durable roof to tlie mine. It con- 

 tains some fossil casts, but not so many as the rock described below. 



150 feet, 



8. Bituminous Coal. — Third and last bed ; this coal is not so 

 compact and glistening in its fracture as the two low^er deposits. Its 

 structure is more slaty ; in burning, it melts and runs together, ob- 

 structing the current of air necessary to combustion, a fact noticed 

 as common to nearly all the upper and last coal deposits. In some 

 of the coal mines the beds are undulating or broken, forming small 

 "/auZ/5," but never so large as to cause much inconvenience to the 

 miner. The water which collects, is generally drained off easily by 

 shallow trenches, as the dip is but small. The slate or shale, on 

 which the coal rests, contains many impressions of plants, but more 

 arundinaceous and culmiferous species than the lower beds, Indicating 

 a considerable ch?nge in the families of plants during the long peri- 

 od of time required to form these immense deposits that are found be- 

 tween the different beds. The impressions on figure No. 61, (page 

 15 of the wood cuts,) are all from this bed with the exception of (e.) 

 which is from a piece in Pomeroy's bed, on the Ohio at Carr's run. 

 (a.) resembles the " Odontopteris Brordii'"' in fruit, most beautiful- 

 ly impressed on an ochre colored ground ; (b.) appears to be some 

 species of grass ; (c.) an asteroid flower which in one place seems 

 attached to the grass, but it is probably only a chance position ; 

 (d.) and (e.) may be single leaves of some large species of Neu- 

 ropteris; (/.) is a ^^Sphenopteris myriophyllum;'' (^.) resembles 



** Odontopteris obtusa. 

 and silicious slate, ov( 



?> 



In the thin bed of shale, between the coal, 



the flattened cast of a large 



trunk, tw^o feet across, with impressions similar to No. 44, only much 



showin 



