72 NON-MARINE FOSSIL MOLLUSCA. 



SPURIOUS AKD DOUBTFUL SPECIES. 



The species mentioned in the following notes were not included in the 

 foregoing list because a part of them do not belong to the non-marine 

 niollusca as they were supposed to do by the authors who first described 

 them; concerning tbe true character of others there is some room for 

 doubt, and the published information concerning the remainder is either 

 unsatisfactory or erroneous. 



In the Annual Report of the Geological Survey of New York for 1839, 

 pp. 65, G6, Mr. T. A. Conrad published descriptions of four species of 

 mollusks from the Medina Sandstone (Upper Silurian) under the names 

 respectively, of Planorbis trilobatus, Cyclostoma pervetusta, Unio primi- 

 genius, and U. orthonotus. All these are now known to be marine spe- 

 cies, and to belong, respectively, to the genera Bucania, Pleurotomaria, 

 Gypricardites, f and Modiolopsis. 



In the American Journal of Science and Arts (1.), Vol. XXIX, p. 149 

 et seq, Plate 1, Pigs. 17-22, Dr. S. G. Morton briefly described and rudely 

 figured five forms which he named, respectively, Unio petrosus, U. tumu- 

 latus, U. terrenus, U. saxulum, and Anodonta hildrethi; and which he 

 reported as having been obtained from Coal-measure strata in southern 

 Ohio. If these fossils were really obtained from Coal-measure strata, 

 our present knowledge of the fauna of that period, at least as it was 

 developed in the region indicated, makes it improbable that they were 

 correctly referred to the genera Unio and Anodonta. It is more prob- 

 able that they were obtained from a post Tertiary deposit, and that they 

 really belong to living species. 



In the proceedings of the Academy of Natural Sciences of Philadel- 

 phia, 1868, pp. 162-164, Dr. Isaac Lea described ten species under the 

 following names, respectively : Unio nasutoides, U. radiatoides, U. subro- 

 timdoides, U. cariosoides, U. humerosoides, U. roanolcoides, U. ligament- 

 oides, U. alatoides, Anodonta grandioides, and A. corpulentoides. They 

 were obtained from a deposit in Xew Jersey which Dr. Lea regarded as 

 "Lower Cretaceous," but which is almost certainly of post Tertiary 

 date. Moreover, they probably belong to the living species, the resem- 

 blance to which is so -plainly indicated by the respective names which 

 Dr. Lea applied to them. 



In Paleontology of California, Vol. II, p. 88, Mr. Gabb speaks of 

 having found the following species of Helix iu a fossil condition, in 

 different parts of that State, part of them being referred to strata of 

 Pliocene age, although the species are all now living in that region : 

 Helix J 'racta Xewcomb, H. hildebrandi Xewcomb, H. mormonum Pit., H. 

 tryoni Newcoinb, and H. tudieulata Binney. 



Mr. H. C. Lea described a shell under the name of Turbo glaber in the 



