132 INVERTEBBA TE FA UNA OF DAKOTA FOBMA TION— WHITE, vol. xvii. 



of the Territories. A part of those discovered by Prof. Miidge are 

 described aud iigured by Mr. Meek in the volume just ineutioued, and 

 a part of them by myself in volume ii of the Proceedings of the U. S. 

 National Museum. Those which were discovered by Prof. Hicks are 

 described and figured in this article. 



Prof. Hicks made his collection about ten years ago and deposited it 

 in the cabinet of the Nebraska State University in 1885. In that year 

 he referred to it in a paper which he read before the American Asso- 

 ciation for the Advancement of Science as representing a marine fauna,* 

 but further study showed it to have been of nonmarine origin. The 

 following description of the locality at which Prof. Hicks discovered 

 these fossils has been given me by him : 



Jefterson C'ounty, Nebniska, 5 miles west of north from Fairbury, about 1 mile 

 from the Little Blue River. The exposure is ti comparatively slight one and occurs 

 upon the north side of a deep ravine, about half way up the slope. Tliis ravine 

 opens into Whiskey Run, and the latter empties into Little Blue River. 



The Dakota strata at this locality, as is usually the case in all that 

 district, consists of ferruginous sandstone, the fossiliferous layers con- 

 sisting largely of impure, partly oolitic, linionite. Fragments and masses 

 of these layers constitute the collection made by Prof. Hicks. These 

 specimens contain an abundance of fossil remains, all of which are 

 either vegetal or molluscan, and all are in the condition of natural casts, 

 molds, or imprints. All the molluscan forms which have been recog- 

 nized are described and figured on following pages. The jilant remains 

 embrace well-known Dakota species. The following have been iden- 

 tified by Prof. F. H. Knowlton, the editor of Lesquereux's work on 

 the Dakota flora, already referred to : Salix meeMi, Newberry, Diospyrus 



primwva, Heer, Sapindus diver sifoliu-s, Lesquereux, Magnolia ? 



(probably new), Plataims prwuvva., Lesquereux. 



All the specimens of the collection being in the condition of natural 

 casts, imprints, and molds, the greater i)art of the studies recorded on 

 the following pages, and all the figures on the accompanying plates, 

 have been made from artificial casts taken from the natural molds. 

 Because of this condition of the specimens the studies of all the species 

 which they represent have been far from complete. So much interest, 

 however, naturally attaches to the division of the Dakota fauna which 

 they represent that, notwithstanding their imperfection, I have thought 

 it desirable to publish them. I have also thought it desirable to give 

 a specific name to each form for purposes of convenience in geological 

 studies, rather than as indicating a satisfactory biological classifica- 

 tion. 



I am indebted to the authorities of the Nebraska State University, 

 through Prof. Erwin H. Barbour, for the opportunity to study and 

 publish this small but interesting collection. All the specimens used 

 in this study are returned to the cabinet of the University at Lincoln, 



Proc. A. A. A. S., vol. 34, pp. 217-219. 



