234 THE DEVONIAN AND CARBONIFEROUS. [bull. 80. 



beds, occurring about the horizou of the Niagara group, are inters trat- 

 ified with beds of greenstones, the whole series being cut by dikes, sim- 

 ilar to regions of the same age in New England. The older Silurian 

 rocks consist of noufossiliferous rocks made up of quartzites and clay 

 slates of great thickness, passing in places into mica, chert, and gneiss, 

 destitute of calcareous, magnesian, and metallic minerals, with the ex- 

 ception of iron pyrites, but including no representative of the Silurian 

 limestones of the United States and Canada, though occurring but a 

 short distance from the Province of New Brunswick. 

 Isaac Lea, 1 in 1859, compared the u Trias w formations of the eastern 



border of the United States with the older rocks of Prince Edward Is- 

 land. 



Mr. Dawson, in referring to the older rocks of Prince Edward Island, 

 had said that they " either belong to the top of the Carboniferous sys- 

 tem or to an overlying deposit of the Permian or Triassic age." Mr. 

 Lea remarked that the rock in the bed of Deep Eiver, North Carolina, 

 formerly considered by Prof. Emmons as Trias, was in 185G by him 

 divided into two groups, Permian and Trias. He considered that the 

 Chatham series of North Carolina, the Newark series of New Jersey, 

 and the Greenfield series of the Connecticut Valley represent one epoch, 

 the Permian. The Groynedd series and that of Phcenixville are evi- 

 dently of the same horizon with the above mentioned. Prof. Em- 

 mons agrees with Mr. Lea in referring these rocks to the Permian epoch, 

 identified as they are in North Carolina by the same Saurian forms, 

 plants, fish scales, and the Posidonia. 



Charles H. Hitchcock, 2 in 1860, made the following correlations of the 

 coal beds of New England : 



By means of the fossil plants Mr. Lesquereux had been able to systema- 

 tize the Carboniferous coals. From comparison of his identifications Mr. 

 Hitchcock concluded that the New England coal basins of Wrentham, 

 Valley Falls, Portsmouth, and Newport, Rhode Island, belong to the 

 lower series, probably below the Mahoning sandstone, and if the upper 

 Coal Measures of other basins were ever deposited there they have been 

 obliterated by denudation. 



In a letter to Mr. B. Silliman, jr., Mr. O. C. Marsh 3 corrected a mis- 

 taken report that the Saurian vertebrae from Nova Scotia (discovered 

 by Marsh in 1855) had been recently found by Agassiz. Mr. Marsh had 

 postponed announcing the discovery, hoping to obtain further remains, 

 but failing to do so, makes it public in this letter, saying that he found 

 the bones beneath 5,000 feet of coal strata; that they resemble the 

 vertebrae of an Ichthyosaurus ; and he proposes for the species the 

 name Eosaurus Acadianus. 



In 1863, in the "Geology of Canada," the Devonian system was recog- 



1 Lea, Isaac: On Age of Trias of Eastern United States. Phila. Acad. Sci., Proc, vol. 10, 1859, pp. 90-92. 

 'Hitchcock, C H. : Synchronism of Coal Beds in the New England and Western United States Coal 

 Basins. Am. Assoc, Proc, vol. 14, 1860, pp. 138-143. 

 3 Marsh, O. O. : On the Saurian Vertehras from Nova Scotia. Am. Jour. Sci., vol. 33, 1862, p. 278. 



