68 PROCEEDINGS OF THK ASSOCIATION OF 



The committee on the time of meeting for 1843, reported the 

 fourth Wednesday of April, which was accepted. 



Prof. W. B. Rogers read a paper "on the Age of the Coal 

 Rocks of Eastern Virginia." He described these strata as occu- 

 pying parts of Chesterhold, Powhatan, Amelia, Henrico, and 

 Goochland counties, and lying in basins of granite, the principal 

 coal seam being separated by only a few feet from the floor of 

 primary rock. In some places near the margin of the field, where 

 alone they have been explored, the thickness of these coal rocks 

 is upwards of eight hundred feet, but towards the centre of the 

 principal basin it is probably somewhat greater. Throughout 

 much of this depth they consist of coarse grits, often composed 

 of the materials of granite so little worn as to present the aspect 

 of this rock in a decomposing state. In this paper Prof. R. 

 shows, on the testimony of fossils, and especially the vegetable 

 impressions found in the grits and slates associated with the coal, 

 that these rocks, instead of being, as had been hitherto supposed, 

 of even older date than th^ great carboniferous formation of the 

 West, and of Europe, belong in fact to a much later period, and 

 correspond nearly, if not accurately, with the bottom of the oolite 

 formation of Europe. The prevailing fossils are of the genera 

 Equisetum^ Tceniopteris, and Cycadites or Pterophjllum, and either 

 agree specifically, or correspond nearly, with those of the oolite 

 coal of Brora and the equivalent beds at Whitby and other 

 places. Prof. R. laid much stress on this determination, as sup- 

 plying one of the links in the geological series not hitherto 

 discovered in this country, and as presenting a stiiking analogy 

 with the abnormal developement of the lower oolite in certain parts 

 of Europe. At the conclusion of the paper. Prof. R. stated that 

 from the fossils he has discovered in a particular division of the 

 new red sandstone of Virginia, he expects ere long to be able 

 confidently to announce the existence of beds in that formation 

 corresponding to the Keuper in Europe. 



Prof. Wm. B. Rogers communicated a paper " on the Porous 

 Anthracite or Natural Coke of Eastern Virginia." In this paper 

 Prof. R. investigates the cause of the peculiar texture and com- 

 position of this material, and points out the forms of vegetation 

 from which both it and the neighboring bituminous coal have 

 been chiefly derived. From the position of the coke beds, as 

 compared wilh those of the bituminous coal, and the frequent 

 interlaminatioii of the two, he proves that the non-bituminous 

 character of the former could not have arisen from the effects of 

 heat on a seam of bituminous coal, but must be ascribed to the 

 thorough carbonization and dessication of the vegetable matter 

 before it was sealed in by the overlying strata. 



