A FOSSIL STARFISH FROM THE CRETACEOUS OF 



WYOMING 



STUART WELLER 

 The University of Chicago 



A specimen of a fossil starfish has recently been presented to the 

 Walker Museum of the University of Chicago, by Mr. N. H. Brown, 

 of Lander, Wyo. The specimen is preserved in a fine-grained, 

 light yellow sandstone from near the summit of the Upper Cretaceous 

 which may be referred to the Fox Hills formation. Though all ' the 

 characters desirable for the classi- 

 fication of the specimen are not 

 perfectly preserved, yet there is 

 justification in the description of 

 such a specimen because of the 

 extreme rarity of such fossils in 

 the Cretaceous faunas of America, 

 and because it is probably the best 

 specimen of a Cretaceous fossil 

 starfish yet found in America; at 

 least no specimen so nearly complete 

 has been mentioned in the literature. 



The specimen is apparently exposed from its dorsal side, but, 

 apart from the large marginal plates, all the plates of this surface 

 have been destroyed. The impressions of the ambulacral furrows 

 of the ventral surface are exposed by the weathering away of the dorsal 

 surface, and appear as rounded, slightly elevated ridges extending 

 from the arm tips to the center of the disk; but the characters of the 

 ambulacra are not sufficiently well preserved to be accurately deter- 

 mined. 



The presence of highly developed marginal plates upon the 

 specimen mark it at once as a member of the order Phanerozonia, 

 and it may be placed, without serious question, in the family Pen- 

 tagonasteridae. The reference of the specimen to its proper genus 



257 



Fig. i. 



