344 GEOLOGY OF THE BLACK HILLS. 



of the Fortieth Parallel, vol. iv, p. 238, Plate 2, Figs. 11-13, from the slates 

 above Call's Fort, North Wasatch Mountains, is perhaps as closely related 

 as any, but differs in having the glabella more rounded in front and propor- 

 tionally broader. 



Formation and locality. — Associated in the same beds and locality with 

 the preceding species. 



SECTION III. 



FOSSILS FROM THE JURASSIC ROCKS. 



RADIATA. 



ECHINODERMATA. 



ASTEROIDEA. 



Genus ASTERIAS Linn. 



ASTERIAS ? DOBIUM. 



Plate 3, fig. 3. 



Asierias? duhium Whitf., Prelim. Rept. Pal. Black Hills, 1877, p. 15. 



Several impressions of a species of Stai-fish, apparently of the genus 

 Asterias, are present in the collection from a bed of light-red sandstone 

 which occurs at a horizon of from 80 to 100 feet above the red Triassic beds. 



The specimens are not in a condition to afford a full description of 

 their specific characters. They are of small size, the rays being from 

 three-fourths of an inch to one and one-fourth inches long, measuring from 

 the center of the body. The rays are slender and flexuous, most of them 

 being more or less curved in their direction and elevated along the middle, 

 as shown on a gutta-percha cast taken in a natural mold of a group of 

 three individuals. The upper surface is subangular, and in structure they 

 are apparently composed of small nodiform plates, placed in longitudinal 

 rows. The center of the body or disk is marked by an obscurely pentan- 

 gular depression on the upper surface. None of the specimens show the 

 under side of the body or rays, so that the characters of these parts are 

 entirely unknown. 



