white.] CKOW CEEEK FOSSILS. - 173 



No. 23. Campeloma mulUstriata Meek & Hayden. 



This somewhat variable species was originally discovered by Dr. Hay- 

 den in the strata of the Fort Union Group at Fort Clark, Dakota, and is 

 described and figured in vol. ix of the United States Geological Survey 

 of the Territories. It was found in great numbers also by Mr. J. A. 

 Allen over a large area of the Upper Missouri Biver region, or, more 

 properly speaking, in the region drained by the Yellowstone. Most of 

 his specimens are larger than either the type-specimens or any of those 

 that were found at the Crow Creek locality. They were also distin- 

 guished by a greater prominence and angularity of the shoulder at the 

 distal side of the volutions, which, to a greater or less extent, charac- 

 terizes the species, but no doubt is entertained of their specific identity. 

 The examples found at the Crow Creek locality are closely like the typ- 

 ical examples, and were obtained only from No. 5 of the section there, 

 its associates being fresh-water forms. No unmistakable examples of 

 this species have been discovered at any locality west of the Rocky 

 Mountains, but some imperfect examples of a closely related, if not 

 identical, species were found in strata of the upper portion of the Bitter 

 Creek series at Point of Eocks and Black Buttes stations, in Wyoming. 

 The fragment of Campeloma found in bed No. 6 of the Crow Creek sec- 

 tion perhaps belongs to this species, but it was too imperfect for specific 

 determination. 



No. 24. Corydalites fecundum Scudder. 



The above name was given by Mr. Scudder, in the Bulletin of the 

 United States Geological and Geographical Survey of the Territories, 

 vol. iV, p. 537, to an insect that laid some remarkable egg-masses, which 

 I discovered associated with a part of the foregoing mollusks in bed 

 No. .3 of the Crow Creek section. No trace of them was found in any 

 other member of the section, nor at any other locality. These egg- 

 masses were found promiscuously intermixed with the shells of branchi- 

 ferous and pulmonale mollusks, and had evidently been drifted more or 

 less from the place of then original oviposition, as had at least a part 

 of the shells with which they were associated. 



Conclusions that in their application pertain alike to all the localities 

 from the strata of which I have made collections of fossils will be re- 

 served for the discussions closing this report, but those observations 

 that were found to be more or less peculiar to separate localities may 

 properly be briefly discussed in more immediate connection with their 

 statement. I may thus especially note here the local and apparently 

 limited development of that member of the Crow Creek section of strata 

 which contains a purely fresh- water fauna. It is true the full extent of 

 that bed is not even approximately actually known, but the locality 

 where it was discovered and examined is apparently its northern border, 

 and no trace of it was discovered at any other locality east of the Bocky 

 Mountains in Colorado. The evidence that its northern border exists at 

 thel ocality mentioned consists in the fact that the bed No. 5 is exposed at 

 only one point, although the whole series of strata which are exposed in 



alone, but it is proper to state that Haldeman's genus Tulotoma was founded upon the 

 shell only, the soft parts, so far as I am aware, having never been described. The only 

 known living American species of Tulotoma, T. magnified, Haldeman's type, is a very 

 variable shell, especially as regards its nodes and carina?, and it may Avell be ques- 

 tioned whether any conchologist would have ventured to' separate the smoother forms 

 from Viviparus if they alone had been known. It is proper to state, however, that the 

 shell of T. magnified is more massive than that of any known living species of Vivipa- 

 ■ run; but, on the other hand, the shell of the fossil species, T. Thompsons, is not thicker 

 than that of Viviparus generally is, except where it is thickened by the nodes. 



