18 THE UNIVERSITY SCIENCE BULLETIN. 



for dispersal. A cool, moist climate similar to that of northern 

 United Slates or southern Canada must have accompanied it. 

 This is shown by the land-shell species found associated w^ith 

 the fresh water. This was also shown by the shells found in 

 the Phillips county Pleistocene which has been reported upon. 

 (Hanna and Johyison, Kan. Univ. Sci. Bui., vol. VII, No. 3, 

 1913.) 



That radical change took place in the climate, fauna and flora 

 of western Kansas after the disappearance of Kaw Lake is evi- 

 dent from the almost complete disappearance of the land and 

 fresh-water mollu^ks, A considerable number of species and 

 at least two genera are not known from Kansas as yet except 

 from Pleistocene fossils. Neither streams nor uplands are 

 fitted for their existence and search must be made for them far 

 to the north before they are located. 



The ants were not particular in choosing material for their 

 "hills." Besides the fossil shells dug from the light buff ma- 

 terial forming the lake deposit they collected a few recent 

 species, probably found living near at hand. There were also 

 sand grains of large size and plant stems, seeds and roots. 



LIST OF SPECIES. 



Sphasrium. What appear to be two species were secured. 

 Any attempt at specific determination in this group of shells 

 at this time would merely add to the already almost inextricable 

 confusion. 



Valvata tricarinata Say. Four specimens. I know of no pub- 

 lished records of this species from Kansas, either living or 

 fossil. Mr. E. C. Johnston collected a dead shell, but not a 

 fossil, at Cameron's Bluff, above Lawrence, Kan., in 1916. No 

 other records are available for the state. 



Lymnxa humilis rustica Lea. One specimen. This form is 

 recorded from Douglas county, Kansas, by Baker {Lymnseidse 

 of N. Am., p. 269, 1911), and is probably the same as was re- 

 corded from the Phillips county Pleistocene as L. humilis. 



Lymnsea pai'va Lea. Thirteen specimens. Previously known 

 from the marl beds of Long Island, Phillips county, and from 

 Douglas county river debris. 



Planorhis antrosus Conrad. Seven specimens. 



Planorbis deflectus Say. Two specimens. Both are small 

 and apparently not full grown. The species lives in Lake View, 



