THE NAUTILUS. 103 



POST PLIOCENE SHELLS. 



BY O. A. CRANDALL, SEDALIA, MO. 



While at Belten, Texas, a short time ago, I discovered great 

 numbers of semi-fossil shells embedded in the clays that were prob- 

 ably formed during the early quarternary period. They are 

 distributed through the clay from two to six feet below the surface 

 and may be seen sticking in the banks at any place along the valley 

 of Nolan Creek where a gully has been washed out. The land is 

 covered with large trees, but the best evidence of the age of the 

 formation is seen in the bed of the creek where the water has worn a 

 channel in the solid limestone rock over which it flows from two to 

 three feet deep. The clay and soil of the valley must have been 

 deposited there before or about the time the creek formed its pre- 

 sent channel, many, many hundred years ago. The clay has 

 preserved the shells, in nearly as good condition (except as to color) 

 as when buried ; and those found at the greatest depth are in the 

 best condition. 



I collected the following species : 



Bulimxdus dealbatus Say. 



Bulimulus schiedianvs Pfr. 



Zonites Jrlabilis W. G. B. 



Zonites — probably an undescribed species. 



Patula alternata mordax Shutt. 



Helix Bcemeri Pfr. var. umbilicus closed. 



Helix Rcemeri Pfr. var. umbilicus closed and toothless. 



Helix Texasiana Moricand. 



Helix Mooreana W. G. B. 



Helix Leaii Ward. 



Helix Berlandieriaua JVIoricand. 



Helidna orhiculata Say. 



Planorbis hicarinata Say. 



Planorhis — probably an undescribed species. 



Limnea umbilicata Adams. 



Physa Halei Lea. 



Pliysa — probably an undescribed species. 



