8 UINTACRINUS: ITS STRUCTURE AND RELATIONS. 



of a colony were found here, weathered out. The deposit was not found 

 in place, but small fragments show that it must have been a large one, for 

 some of them belong to a plate half an inch thick, but entirely destroyed 

 by the erosion of the ravine. One fine calyx, with arms partly preserved, 

 was found here, entangled with parts of other individuals as usual. 



Localihj No. 6. — Two miles northeast of No. 1. This was Professor 

 Slosson's locality, mentioned in Dr. Williston's account in the Kansas Uni- 

 versity Quarterly, already cited. The description of the occurrence has 

 already been quoted supra. The deposit was entirely exhausted, but at a 

 point about one-eighth of a mile distant I found the weathered fragments 

 of what may have been another colony. Locality No. 6 a, among which 

 were several fairly good specimens. 



Locality No. 7. — Seventeen miles west of No. 1. Fragments with a good 

 calyx and arms were found here some years before, but no deposit in situ. 



Weathered fragments have been picked up in three or four other spots 

 in the same region, but they may have all been derived from the above 

 mentioned localities, transported a great distance by wind or water. 



OCCURRENCE AND DISTRIBUTION. 



Having been found in Utah and Kansas, in localities over five hundred 

 miles apart, it is evident that Uintacriims socialis was widely distributed, and 

 its fossil remains may be looked for in America wherever the upper part 

 of the Niobrara Chalk is exposed. Being a free floating Crinoid, it might 

 be expected to have abounded irregularly throughout the great shallow 

 interior-continental sea, in which the chalk bottom was forming.* 



Nevertheless, it is somewhat remarkable that so few of them have been 

 found, considering the great extent of the formation and the favorable 

 character of its exposures. The Niobrara Chalk has been searched bv 

 organized parties and individual collectors almost every year since the 

 first important discovery of saurian remains in 1870 ; and ever since Mudge 

 found his weathered specimens of U. socialis, in 1875, collectors have been 

 on the lookout for Crinoids. Yet with the exception of a few other frag- 

 mentary weathered specimens found by Williston and Cooper, the colonies 

 found by Slo.sson, Martin, and myself are all that have ever been brought 

 to light. When we consider how wonderfully prolific this formation has 



« Dana's Manual of Geology, 4tli Ed., p. 826. 



