NOTES 



SoMS Noteworthy Accessions to the Division oe Invertebrate 

 Paleontology in the National Museum 



(With Two Plates) 



Mr. Frank Springer, of Burlington, Iowa, has deposited in the 

 U. S. National Museum a second slab of the unique crinoid Uinta- 

 crinus socialis, which, like the first (see Smithsonian Miscellaneous 

 Collections, Quarterly Issue, Vol. i, 1904, p. 450), deserves mention. 

 Both of these slabs are now on exhibition, having been mounted on 

 the wall facing the corridors of the southeast balcony. The one 

 specimen so supplements the other that the Museum now has un- 

 doubtedly the finest exhibit of this crinoid extant. The first slab 

 was one of several pieces making up a mass originally less than one- 

 half an inch thick, and fifty feet long by twenty feet wide, collected 

 in the upper part of the Niobrara chalk near Elkader, Logan County, 

 Kansas. The bodies of about 140 of these crinoids can be counted 

 upon the surface of the first slab, but the position of the crinoid 

 crowns is such in most cases that, although exceptionally well placed 

 to show their plate structure, they seldom exhibit the complete body 

 and full length of arm. In this latter respect, the second slab is par- 

 ticularly fine, as a glance at the accompanying plates will show. 



The slab lately sent by Mr. Springer is nearly six feet square and 

 shows upon its surface over one hundred more or less perfect indi- 

 viduals. It comprises a colony of the Uintacrinus found twenty 

 miles west of Elkader, Kansas, in the Hesperornis bed of the upper 

 Niobrara chalk, about the top of the blue chalk where the change in 

 color to yellow has commenced. This horizon has furnished prac- 

 tically all of the Kansas specimens of Uintacrinus, and this recent 

 discovery has extended the geographical range in this state to an 

 area about 60 miles in diameter. 



Mr. Springer's studies of Uintacrinus have been so thorough that 

 nothing new of scientific interest was brought out in this latest find, 

 but as a Museum exhibition specimen, the slab is unique. The 

 reason for this lies in the exceptionally regular arrangement and 

 position of the bodies and their corresponding arms. In many of 

 the specimens hitherto found, the bodies have been crushed and the 

 arms so flattened out or matted together and entwined that the full 

 length could seldom be traced. In the present specimen, the bodies 



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