144 GEOLOGY AND PALiEONTOLOGY. 



POLYPI. 



TUKBINOLIA, Lam. 



TURBINOLIA, TEXANA. 



Plate II, Fig. 3, a, b. 



Horn-shaped, curved, with transverse, obtuse undulations; radii equal, prominent, numerous, 

 (about 50 in number,) transverse section oval. 



Locality. — Between El Paso and Frontera. 



There are two specimens of this fossil in the collection, but the cup in each is filled with a 

 portion of the limestone in which they were imbedded, and the characters are thus concealed. 



ECHINODERMATA. 



Several species of this family occur among the collections of the Boundary Survey. Three of 

 these are identical with species described by Dr. F. Eoemer, in his Kreidebildungen von Texas, 

 while two others are quite distinct. Owing to the imperfection of the specimens in the collec- 

 tion, some of the figures have been copied from the work cited. It was not until the collections 

 of the second survey of the Boundary were received that the Toxaster elegans was observed, and 

 it has been figured on the supplementary plate 21. The association of these and other species 

 with the well known cretaceous fossil Gryphcea Pitcheri, figured upon the same plate, leaves 

 nothing further to be desired in proof of the age of the formation.* 



PYEINA PARRYI, Hall. 

 Plate I, Fig. 1, a-d. 



Shell oblong ovoid, or somewhat pentagonal, with the angles rounded, convex above and 

 concave in the middle beneath; apex central, flat or slightly depressed, prominently convex in 

 front, and subtruncate behind; mouth central, oval; anus ovate, narrower above and situated 

 centrally between the upper and lower side of the shell ; ambulacral areas somewhat prominent 

 or slightly elevated above the rest of the surface. Tubercles on the upper side scattered, with 

 granular spaces between, becoming more numerous on the sides and crowded on the base of the 

 shell. Length 1^ inches ; width 1^ inches. 



The general contour of the fossil is a broad oval, slightly narrower behind and subtruncate; 

 while the elevation of the ambulacral space in front gives it a slight prominence in that part. 

 This prominence of the ambulacral spaces likewise often gives an obtusely pentagonal form to 

 the shell ; but this character is not constant, nor is the slight prominence in front observable in 

 all specimens. 



This neat and pretty species is readily distinguishable from any other yet described from the 



cretaceous rocks of the southwest. 



« Prof. Agassiz, to whom these fossils were submitted, expressed his opinion that they were from the lower cretaceous 

 formation. 



