^\o.i.] WHITE ON CAEBONIFEEOUS AND CEETACEOUS FOSSILS. 211 



proof of the fact, because it possesses no cliaracteristic Permian types^ 

 or at least none which are not also common to the great mass of Carbon- 

 iferous strata beneath. These remarks apply especially to the Carbon- 

 iferous series as it is developed in Colorado, Utah, Wyoming, and Idaho, 

 and not to the region farther eastward, where true Permian strata 

 probably exist. 



In the TVestern Territories the Arhole Carboniferous series reaches an 

 aggregate thickness of 4,000 or 5,000 feet; and although the strata of 

 the middle portion are, as a rule, more fossiliferous than the others, yet 

 fossils are occasionally found both near the base and the top of the series. 



From what has already been remarked it will be seen that so far as 

 invertebrate fossil's are concerned, there is great faunal uniformity 

 throughout the whole of this great thickness of strata; and, further- 

 more, that the prevailing characteristics of that fauna are those of the 

 Coal-measure — especially the Upper Coal-measure — fauna of the Missis- 

 sippi YaUey. 



The new specific names which are applied to a part of the forms 

 noticed on the following pages, especially the N'ucidana and Bellerophon^ 

 have not been given without some hesitation, because of the close re*la- 

 tionship which those forms respectively bear to certain others which are 

 already known and specifically named. The differences seem to be 

 sufficient, however, to warrant this course in accordance with the pres- 

 ent usage of paleontologists, and it is further warranted by the neces- 

 sity of designating those forms by name, that geologists may use them 

 for the purpose of characterizing the strata or the horizons to which 

 they belong. The horizon of the two forms especially referred to is 

 doubtless somewhat higher in the Carboniferous series than the one 

 which the representatives of these species in part characterize in the 

 Mississippi Valley; but Mr. G. K. Gilbert, who collected them, was not 

 entirely satisfied that the strata from which they came were really the 

 uppermost of the Carboniferous series. 



ACTINOZOA. 



Genus Leptopora Winchell. 



Leptopora "vyinchelli (sp. nov.). 



Among some collections brought in by Dr. A. C. Peale from near the 

 forks of Logan Eiver, in Bear Eiver Eange, near the northern boundary 

 of Utah, are a few specimens of Leptopora. This genus of corals was. 

 proposed by Dr. AYinchell in the Proc. Acad. Nat. Sci. Philad. 1863, 

 p. 2, for a peculiar form, the first, and hitherto the only known, species 

 of which occurs in the Kinderhook division of the Subcarboniferous 

 group at Burlington, Iowa. Being so rare a form, and consequently 

 so little known, I quote Dr. Winchell's generic diagnosis as follows : 



"Corallum occurring in thin discoidal masses; cells very shallow, 

 . crowded, polygonal, separated by a common cell-wall which is vertically 



