L— PRELIMINARY PALEONTOLOGICAL REPORT, 



CONSISTING OF 



LISTS OF FOSSILS, WITH DESCBIPTIONS OF SOME NEW 



TYPES, ETC. 



By F. B. Meek. 



GENEEAL EEMAEKS.* 



The few Silurian fossils enumerated in the following list appear, 

 judging from their affinities, to belong to a low horizon in that series or 

 system of rocks. Ophileta complanata, as is well known, occurs in the 

 calciferous group of the Lower Silurian in New York. The specimens 

 in the collection referred to this shell are smaller than the usual size of 

 Yanuxem's species, and may possibly belong to a distinct representative 

 form, though they seem to agree in all respects, excepting in size, with 

 0. complanata. An associated sub-discoid shell, belonging apparently 

 to the genus Rapliistoma, is also nearly allied to a species found along 

 with 0. complanata in rocks of about the age of the calciferous along 

 Lake Pepin in Minnesota and Wisconsin. Another little gasteropod, 

 however, found associated with those mentioned above, and for which I 

 have proposed the name Bucanella nana, is not only congeneric with, but 

 even specifically allied to one found in the Medina sandstone, and some 

 of the higher rocks in New York, though it is nevertheless specifically 

 distinct from the New York form. So far as tke&e few fossils warrant 

 the expression of an opinion respecting the age of the rocl? from which 

 they were obtained, I should be inclined to place it nearly on a parallel 

 with the calciferous division of the Lower Silurian. 



The rock from which the single Orthis was obtained at Colorado City 

 is probably also Lower Silurian, as this shell belongs to a section of the 

 genus found in rocks of that age, and is unlike any carboniferous or 

 Devonian form known to me. 



In regard to the carboniferous species mentioned in the following list, 

 I have elsewhere remarked that although some of them "are forms 

 known to be common to the lower carboniferous and the coal measures 

 of the Western States, they are all, with one or two exceptions, so far 

 as they have been identified, found in the coal measures of Illinois, Iowa, 

 Kansas, and Nebraska, while not a single one of them is identical with 

 any of the species peculiar to the carboniferous limestone series below 

 the horizon of the millstone grit in the Western States, though about 

 fourteen of them are peculiar to the coal measures there." t 



From these facts it would seem that if the lower carboniferous lime- 

 stones of the Mississippi Valley are represented at the localities from 

 which these collections were obtained, they probably contain few fossils, 

 and that the principal fossiliferous carboniferous strata there belong to 

 the horizon of the coal measures, as developed farther eastward. We 



* I am under obligations to Professor Henry for the usual facilities at the Smithsonian 

 Institution, while preparing this paper. 

 t Proceed. Am. Philosoph. Soc, Phila., XI, p. 428, 1870. 



