eXll PHOCEEDINGS OF THE aEOLOGICAL SOCIETY. 



posed to be hardened Petroleum, the solidification of which must 

 have taken place at a very early geological period. 



In the ' Bulletin ' of the G-eological Society of France (2nd ser. 

 vol. xxi. p. 132) is an account of the geology of Nebraska, by M. 

 Jules Marcou. His object was to connect his observations on 

 Lake Superior with those which he had made on the banks of the 

 Eio Grrande del Norte. He describes the sections, seen to great 

 advantage in the Bluffs, on the banks of the Upper Missouri, and 

 particularly in the neighbourhood of Nebraska city. The base of the 

 section consists of red arenaceous marls, sometimes micaceous and 

 slightly schistose, becoming green in the upper part, and containing 

 thin plates of red sandstone, and nodules of marly limestone contain- 

 ing fine specimens of a Productm allied to P. Cancrini, but larger. 

 These are overlain by cream-coloured and slightly dolomitic lime- 

 stones, with many stems of Encrinites, alternating with bands of 

 black clay containing thin seams of coal. The only other fossils 

 in this division are anew species of Spirifer and a new Allorisma. 

 The next division (C) is 34 feet in thickness, and very fossiliferous. 

 In the lower portion a new Procluctus is very abundant, also a 

 small Spirifer, and a Terehratula allied to T. suhtilita. Above this 

 is a bed of mottled plastic clay, containing a vast abundance of 

 fossils, perfectly preserved, and of a delicacy rather resembling that 

 of Tertiary fossils than of those of the age of the New Eed Sand- 

 stone. Most of these are new, and belong to the genera Edmondia, 

 Aucella, Avicula, Leda, Myaliiia, Monotis, BaTcewellia, Pecten, Lima, 

 Apiocrinites, Stenopora, and Synocladia. There are also two species 

 of Brachiopods, very abundant, one of which appears to be iden- 

 tical with Spirifer Glannyamis, King, and the other with CJionetes 

 inucronata. Meek. Other fossils also occur rather higher up. 

 The whole assemblage is considered by M. Marcou as resembling 

 the Dyassic fauna of Saxony, and he considers the beds of Nebraska 

 city as belonging to, and representing in America, the upper por- 

 tion of the Dyas of Europe. 



Another locality, rich in these same fossils, is the immediate 

 neighbourhood of a town called Plattesmouth, near where the 

 river Platte falls into the Missouri, twenty-five miles to the north 

 of Nebraska city. The beds are all different from those of Ne- 

 braska city, and belong to the lower portion of the Dyas. The 

 fauna of these lower beds, although eminently a New Red Sand- 

 stone fauna, nevertheless resembles that of the Carboniferous beds 

 which lie below, and are considered by M. Marcou as a marine 

 equivalent of the Eothliegende of Grermauy and Eussia. Five 

 miles off, near Bellevue, the Carboniferous Limestone is brought up, 

 having a slightly different dip and inclination, namely, 6° to the 

 west instead of about 4° to the south-west. This Dyas formation 

 is described as lapping round the masses of Carboniferous Lime- 

 stone, which probably existed as islands or reefs in the Dyassic sea. 



After describing other localities where he foimd a fauna in the 

 Carboniferous series identical with that which he had found in the 

 Mountain-limestone rocks of Pecos and Tigeras, and on the top of 



