332 ANNUAL OF SCIENTIFIC DISCOVERY. 



as well as the Middle Virginia belt, ought to be placed in the Jurassic 

 series, not far probably above its base. 



In North Carolina, on the Dan River, where these rocks include one or 

 more thin seams of coal, the same Cypridee and Posidoiiiee are found in 

 great numbers in some of the fine-grained shales and black fissile slates. 

 The latter were noticed as early as 1839 by Dr. G. W. Boyd, while on the 

 Virginia Geological Smrvey. Regarding this fossil, of which specimens 

 were also obtained about the same time from the middle belt in Virginia, 

 as identical with the Posidonia of the Keuper, Prof. R. had, many years 

 ago, announced the probability that a part or all of the great western belt 

 was of the age of the Trias, instead of being lower in the Mesozoic series. 



Specimens of the Posidonise and Cypricla?, from both belts in North 

 Carolina, and from the eastern and middle belts in Virginia, were ex- 

 hibited by Prof. R. at the Albany meeting of the American Association of 

 Science in ISol, for the purpose of showing the close relationship between 

 these deposits in geological time. Among the specimens from the Dan 

 River, Prof. R., on the present occasion, referred to the impression of a 

 Zamite leaf and a joint of Equisetum Columnare. Prof. Emmons, in the 

 report above referred to, speaking of the marly slate of this system, says 

 that " it differs in no respect from that of Deep River, bearing the same 

 fossils, Posidonia and Cypri-s, in great abundance." In the same belt in 

 Pennsylvania, in the vicinity of Pho?nixville, early last spring, Prof. 

 II. D. Rogers discovered Posidonite in great numbers in a fissile black slate, 

 and on subsequent examination the same beds were found to contain lay- 

 ers crowded with the casts of Cypridce. Along with these are multitudes 

 of Coprolites, apparently saurian, resembling in size and form the Copro- 

 lites found in the carbonaceous beds on Deep River, and also some imper- 

 fect impressions of Zamite leaves. These facts Prof. R. considers sufficient 

 to identify, as one formation, the discontinuous tracts of this belt in North 

 Carolina and Virginia, and the great prolonged area of the so called New 

 Red Sandstone of Maryland, Pennsylvania and New Jersey. 



As to the geological date of this belt, Prof. Rogers said that the dis- 

 covery at various and remote points of its course, of Posidonia?, Cypridse 

 and Zamites, most or all of which are identical with these forms in the 

 eastern and middle secondary areas of Virginia and North Carolina, makes 

 it extremely probable that the rocks, formerly referred to the New Red 

 Sandstone, and of late more specially to the Trias, are of Jurassic date, 

 and but little anterior to that of the coal rocks of Eastern Virginia. 



Prof. R. considered the occurrence of Cypridse abundantly in all these 

 belts as a strong evidence of their Jurassic age. While only a few species 

 of Cypriclro and many of the allied genus Cytherina occur in the Silu- 

 rian and Carboniferous rocks, there is a total absence of these Crustacean 

 remains throughout the series^ of deposits extending from the base of the 

 Permian to the lower limits of the Oolite. But on entering the latter the 

 Cypridaj reappear and become very abundant, there being no less than 

 twelve species known to belong to the Oolite formations of Europe. 



