TITLES AND ABSTRACTS OF PAPERS 211 



stratigraphie and paleogeographic results of Dr. Kindle's work in this fa;* 

 northern area. 



PALEOZOIC SECTIOX OF THE LOWER MACKENZIE RIVER 

 BY E. M. KINDLE 



The hist paper of the afternoon was an account of the Iowa Devonian 

 ec-hinoderms, given by the author and illustrated by numerous well 

 selected lantern slides. It was discussed by Professor Jackson, who ex- 

 pressed his appreciation of the detailed studies of the author upon Iowa 

 Devonian fossils. 



ECHIXODERMS OF THE IOWA DEVOXIAX 

 BY A. O. THOMAS 



( Abstract) 



The investigations of Hall, White, Whitfield, Barris, Wachsmuth and 

 Springer, and others have made known at least sixteen species of echinoderms 

 collected in Devonian formations within the borders of Iowa. 



The descriptions of the known forms are widely scattered through the liter- 

 ature: in this paper these are brought together and a few of the species are 

 redeseribed in the light of new material. A number of undescribed species in 

 the Calvin Collection, together with several secured by the author during a 

 study of the Iowa Devonian for the Iowa Geological Survey, brings the total 

 number of species up to thirty. Four classes of echinoderms are represented, 

 the most abundant being the crinoids. A l)rief analysis of the fauna follows. 



The cystids are represented by two species of the genus StroMlocystites, 

 one of them being new and differing from the other, S. calvini Whiter, in hav- 

 ing unbranched ambulacra, nodose ambulacral plates, and smooth thecal 

 plates. These cystids occur in the Cedar Valley limestones and are relatively 

 rare. 



The blastoids include one pentremite, J*cntremitidca siihtriuicatus (Hall), 

 and three species of Xucleocrinns. Two of the latter are described by Barris 

 in the Proceedings of the Davenport Academy of Science, and the third is new. 

 The new species has a large calyx, which in cross-section is sharply stellate, 

 and its very narrow ambulacra are elevated upon the longitudinal keel-like 

 edges. 



The crinoids, especially the camerates, are very common and in places their 

 remains make a crinoidal limestone. Of the Melocrinidaj there are five species 

 of Mclocrinus ; these are M. nodosus Hall, from near Iowa City; M. tiffani/i 

 Wac-hsmuth and Springer, from Solon : a new species with extremely nodose 

 plates from Brandon, and another with a large bowl-shaped cup and smooth 

 plates from Kockford. Dolatocrinus trladactylus Barris, Stereocrinus trian- 

 fjuhitiis Barris, and a new Stereocrinus from Littleton with stout spines on 

 the costals complete this family. The Batocrinidie are abundantly represont«'<l 

 by the well known Mcfjistocrinus fanisirorthi White, ^f. latus Hall and M. 

 nndosus Barris are nuich less common. The Hexacrinida^ include the type and 

 o\\\\ specimen of Hcrarrinus oofidentnUs Waclismuth and Springer from 



