256 Remarks on American Rock Formations. 



of such rocks, (old rocks with mechanical products,) and the 

 nearer they are to the level of the ocean, the more likely they 

 are to be horizontal. This rule is the result of observation, 

 and of a theory, which I may, hereafter, give to the world. 



In the states of Ohio, Kentucky and Tennessee, the oldest 

 rocks, or those lowest in position, I found to be characterized 

 by the same shells and fossils found at Trenton Falls in New 

 York, which are similar to the shells and fossils, which char- 

 acterize the transition rocks of Europe, namely, the orthocera- 

 tite^ trilohite^ productus spirifer, and others of the new genera 

 of Sowerby. To these may be added the many species of 

 fovosi, and the isotelus of De Kay, which 1 found in this, 

 at Frankfort in Kentucky, and at Nashville in Tennessee. 

 All these products I observed were below the bituminous 

 shale ; for where it commenced these products disappeared, 

 the encrinite taking their place along with terehratula. 



Above the coal shale were terehratula, and that species 

 of Linnasan madrepora now the genus stylena. Those 

 formed the characteristic of the most modern rocks I met 

 with. It is worthy of remark, that all the barrens I crossed 

 over, consisted of the rocks above the shale ; and the finest 

 lands of the three states I visited, had their soil underlaid 

 with the rocks below the shale. In these latter, httle or no 

 siliceous particles are observable, whilst, in the rocks above 

 the shale, they abound ; they form nodules, irregular masses, 

 &c. All the stylena, which are very numerous, are replaced 

 with silex. It is to these siliceous masses, that the barren 

 nature of the country is owing ; for drought being frequent, 

 and they being good conductors of heat and bad absorbers 

 and retainers of moisture, vegetation does not find the con- 

 ditions for vigorous life, as is found where they are absent. 



Most of the French geologists I studied with, assigned to 

 the transition the bituminous coal deposition, making it the 

 last member of that class; so with those, who are governed 

 by authority, I presume, this will have weight. With myself 

 it is sufficient to know, that the shells and fossils mentioned, 

 are of the same genera with the transition rocks of Europe — 

 our types; that, as in our country, they abound in such 

 rocks, and if found in ^nore modern rocks, they occur but 

 occasionally ; that such rocks in the western country contain 

 iio coal ; all the coal there, is in rocks posterior to them. 



