COAL ROCKS OF EASTERN VIRGINIA. 301 



many years ago, and lately examined and named by onr able 

 icthyologist, Mr. Rediield. 



The coarser rocks, lying above the carbonaceous strata, and 

 forming the greater part of the thickness of the series, contain very 

 few organic remains, and those in so imperfect a condition as to 

 liave little or no value for purposes of comparison. There are, 

 however, strong reasons for believing that these strata, by a grad- 

 ual transition, pass upwards into the series of felspathic sandstones, 

 described in my Report of the Geological Survey of Virginia for 

 1840, under the title of Upper Secondary Strata. The latter, 

 considered by Messrs. Taylor and Clerason, as " of secondary 

 origin, perhaps coeval with the Oolites," have since been referred 

 by myself and Prof. H. D. Rogers, to the upper part of the Oolite 

 series, so that this great division of the geological column, though 

 still perhaps very imperfectly represented in the United States, 

 comprises a thickness of considerably more than one thousand 

 feet of strata. 



I may here incidentally remark, that certain fossils {Posidono- 

 mya Keuperi ? ^-c.) which I have recently found in a particular 

 division of the new red sandstone [Middle secondary) of Virginia, 

 have led me to infer the existence in that formation, of beds cor- 

 responding to the Keuper of Europe. A more particular account 

 of this discovery is reserved for a future occasion. 



The following descriptions of some of the principal fossil plants, 

 found in connection with the Oolite coal of Eastern Virginia, are 

 the results of a careful comparison of the specimens with the 

 figures and descriptions of analogous fossils, in Sternberg, Brong- 

 niart, Bronn, Lindley and Hutton, Phillips, and the Memoirs of 

 Murchison, Grant, and others relating to the subject. These, with 

 others not yet ready for the press, will, I trust, fully sustain my 

 conclusion as to the age of the remarkable coal-formation under 

 consideration. 



The details which they include, though inconsistent with the 

 elegance of technical description, together with Plates XIII and 

 XIV, wih, it is believed, facilitate a just comparison of these fossils 

 with those of the Oolite coal-formation elsewhere. 



