Some Additions to the Cretaceous Inverte- 

 brates of Kansas. 



BY W. N. LOGAN. 



With Plates XX, XXI. XXEI, XXIII. 



In volume IV of the Kansas Geological survey reports the writer 

 published a preliminary report on the invertebrates of the upper 

 Cretaceous formation of that state. Since the time of the prepara- 

 tion of that report I have made additional collections and present 

 in this article the results of my further investigations. Five of the 

 forms herein described belong to the lower Cretaceous beds, two 

 forms to the Dakota and the remaining forms to the Niobrara divis- 

 ion of the upper Cretaceous. 



The Dakota in Kansas is subdivided into two groups, the salifer- 

 ous and the ferruginous. The collections were made from the 

 latter. They consist of casts and impressions in the sandstone. 



The Niobrara is subdivided into the Ft. Hays limestone and the 

 Pteranodon beds, the latter being subdivided into the Rudistes 

 beds and the Hesperornis beds. The majority of the specimens 

 were collected from the Rudistes beds. A few forms, however, 

 were collected from the Hesperornis beds.* 



The specimens collected consist for the most part of well pre- 

 served shells. In a number of the specimens the coloring matter 

 of the periphery of the shell is so well preserved as to present the 

 appearance of a shell in its living state. This fact points to the 

 conclusion that the shells were imbedded in the stratum of chalk 

 before they had weathered to any perceptible degree. From which 

 we are led to believe that the deposition of the forms which com- 

 pose the chalk was very rapid. Further evidence of the powerful 

 preservative agency of the chalk is also secured. The water in 

 in which these forms were deposited must have been undisturbed 

 bv waves or currents else the shells would have worn more or less 

 by corrosion. The water was in all probability deep sea water 

 which did not lie in the scouring path of any deeply iiowing cur- 



*Four of tlie spe*!inLMis herein described were obtained through the Ivindness of Dr. 

 S. W. Williston of Kansas University. The remaining ones were collected by the writer. 



(87) KAN. UNIV. QUAK., VOL. VIII, NO. 3, APR., 1899, SERIES A. 



