Ifesozoic and GcBnozoic Geology and Palaeontology. 221 



California, Delphinus OGciduus; from Washington county, Texas, An- 

 chippus texanus; from the Bad Lands of Nebraska, Lophiodon occiden- 

 tale, and from Shark river, Monmouth county. New Jersey, Anchippo- 

 dus riparius. 



T. A. Conrad* described, from the Miocene of the Atlantic coast, 

 Volutella oviformis, Prunum virginiana, now Marginella virginiana, 

 Mercenaria cuneata, Caryatis pUonema, Garditamera recta ; and from 

 Wyoming, Goniobasis carteri. 



Prof. 0. C. Marshf described, from the Tertiary at Antelope station, 

 on the Union Pacific Railroad, 450 miles west of Oraaha, in Nebraska, 

 Equits parvulus, now Protohippus parvulus. 



The Tertiary underlies a wide central belt in West Tennessee, and 

 was subdivided by Prof. Safford,J in 1869, in ascending order, into 1, 

 Porters' Creek Group ; 2, Orange Sand ; 3, Bluff Lignite ; 4, Post- 

 pliocene beds, on the Mississippi Blutf, consisting of Bluff gravel and 

 Bluff loam ; aud superficial gravel beds, in other parts of the State, 

 consisting of ore-region gravel, eastern gravel, and lastly of bottoms, 

 and alluvial beds. 



The Bluff' lignite consists, especially in the middle and southern 

 parts of the State, of a series of stratified sands, with more or less 

 sandy, slaty clay, characterized by the presence of well-marked beds 

 of lignite; though, in the northern part of the State, its upper portion 

 is frequently more or less indurated, presenting layers of soft sand- 

 stone with less lignite. The upper part of the series is generally well 

 exposed below the gravel of the Mississippi Bluffs. At Memphis, how- 

 ever, it scarcely appears above low-water. About one hundred feet 

 of the series has been seen. In this thickness it contains from one to 

 three beds of lignite, which are from half a foot to four feet in 

 thickness. 



The outcrop of the Orange sand or Lagrange Group, foi-ms more 

 than a third of the entire surface of West Tennessee. It occupies a 

 belt, about 40 miles wide, which runs in a northeasterly direction, 

 through nearly the central portion of this division of the State. As 

 seen in bluffs, railroad cuts, gullies, and in nearly all exposures, it is 

 generally a great stratified mass of yellow, orange, red or brown, and 

 white sands, presenting occasionally an interstratified bed of white, 



* Am. Jour. Conch., vol. iv. 



t Am. Jour. Sci. & Aits, 2d series, vol. xlvi. 



X Geo. of Tenn. 



