28 Cincinnati Society of Natural History. 



and other places in Nebraska (Fort Piei-re Group), Ptychoceras mor- 

 toni, Fasiis suhtiirritus, now Pyrifusus subturritus, J^\ intertextas, now 

 P. intertextus^ Xylophaga elegantula, now Tarnus elegantnlus, X. 

 stimpsonij now T. stimpsoni; from (Fox Hills Group), near the mouth 

 of Heart river, Fasus vaughni; and from other parts of Nebraska, 

 Fastis (?) scarhoroughi^ now Fasciolaria scarboroughi^ Pkoladomya 

 subventricosa, Cyprina cordata, now Sphceriola (?) cordata, C. eom- 

 2)ressa, C. subtmnida, C. ovata, JPectunculus subimbricatus, now 

 Axincea subimbricata, Ostrea translucida^ Hemiasterhumphreysanus', 

 from the mouth of Judith river, Vitrina obliqua, Planorbis amplexus^ 

 Helix occidentalism now Hyalina occidentalism H. vitrinoides, now 

 H. vetusta, 3Ielania omitta, now Goniobasis omitta, 31. subtortu- 

 osa, now G. subtortuosa, 31. subkevis, now G. sublaivis, 31. invenusta, 

 now G. invenusta, Unio danai, U. detce}/anus, U. subspatulatiis.^ 

 Ostroia glabra; from the Fort Uaion Group, Lignite beds at Fort 

 Berthold on the Missouri river, Planorbis fragilis, now P. planocon- 

 vexus, 3Ielania tenuicarinata., now Goniobasis tenuicarinata, 31. 

 warrenana, now Hydrobia warrenana; from the Fort Benton Group, 

 at th'e mouth of Vermilion river, Serpula tenuicincta; from the Da- 

 kota Group, near the mouth of Vermilion river, Soloi dakotensis, now 

 Phorella dakotensis^ and Cyprina arenaria, now Cyrena arenaria. 



The rocks* of the Lower Cretaceous, in Mississippi, consist princi- 

 pally of stratified sand, mixed with a large proportion of silicate of 

 iron or glauconite, which imparts to it a greenish color of different 

 hues, and has given origin to the very appropriate name of greeusand. 

 The indurated greensand is generally full of fossils. It is exposed in 

 the western part of Tishamingo, eastern part of Tippah, northwestern 

 part of Itawamba, northeastern part of Pontotoc, and northeastern part 

 of Lowndes county. 



The Upper Cretaceous has sometimes been called the rotten lime- 

 stone, and occupies a larger area than the lower division. It occupies 

 part of Kemper, Noxubee, Lowndes, Ocktibbeha, Chickasaw, Monroe, 

 Pontotoc and Itawamba counties. This division is also highly fossil- 

 iferous where well exposed. The estimated thickness of the whole is 

 placed at from 1,200 to 1,500 feet. 



Dr Leidyf described, from Columbus, Miss., Hadrodus priscus; from 

 Nebraska, Phasganodus dims, and from the greensand of New Jersey, 

 Pycnodus robustus. 



* Geo. of Miss. 



t Proc. Acad. Nat. Sci., vol. 9. 



