608 GEOLOGY OF THE YELLOWSTONE NATIONAL PARK. 



ANNOTATED LIST OF SPECIES, WITH DESCRIPTION OF NEW 



FORMS. 



TRIASSIC (?) SPECIES. 



LINGULA sp. undet. 



A few specimens of Lingula from beds on the summit of Quadrant 

 Peak, supposed to be of Triassic age, closely resemble the Jurassic Lingula 

 brevirostris M. and H. from the Black Hills. 



JURASSIC SPECIES. 

 ECHINODERHATA. 



Pentacrinus asteriscus Meek and Hayden. 



Pentacrinus asteriscus Meek and Hayden, 185S: Proc. Acad. Nat. Sci. Phila., p. 49. 



White, 1875: Geogr. and Geol. Surv. W. 100th Meridian, Vol. IV, Pt. I, p. 162, 



PI. XIII, figs. 6a, b. Clark, 1893 : Bull. U. S. Geol. Surv. No. 97, p. 26, PI. Ill, 



figs. 2a-d. 

 Pentacrinites asteriscus Meek and Hayden, 1S65: Palneont. Upper Missouri, p. 67, PI. 



Ill, figs. 2«, b, and fig. in text. Whitfield, 1880: Geol. Black Hills Dakota, p. 



345, PI. HI, figs. 1, 2. 

 Pentacrinus ichitei Clark, 1893 : Bull. U. S. Geol. Surv. No. 97, PI. Ill, figs. ia-c. 



This species, which is known only from portions of the columns, occurs 

 in collections from divide between Fawn Creek and Gallatin Valley, from 

 the slopes of Mount Sheridan, and from west of Snake River, north of Berry 

 Creek. 



The joints of the columns vary in diameter, in thickness, and in the 

 depth of the reentrant angles, but they do not vary more in these respects 

 than do the different portions of the stem in a single individual of a recent 

 Pentacrinus. The joints of the upper part of the column are always thinner, 

 more distinctly star-shaped, and differ in all other details from those of the 

 lower portion. 



The name P. whitei was proposed by Prof. W. B. Clark for large, thin 

 joints with deep reentrant angles, but the author of the species informs me 

 that he has abandoned the name for reasons similar to those just given, and 

 in a forthcoming monograph of the Mesozoic Echinodermata of the United 

 States he will refer all the known American Jurassic Pentacrini to P. asteriscus. 



