30 James E. Conkin, Barbara M. Conkin, William T. Mason, Jr. 



Stratigraphic and Geographic Occurrences 



Pleistocene mollusks were reported from the undifferentiated Ber- 

 clair terrace of Blanco Creek, Bee County, Texas and from Pleistocene 

 deposits in San Patricio County, Texas by Sellards (1940); in addi- 

 tion, Conkin and Conkin ( 1962 ) reported Pleistocene ( Late Wiscon- 

 sinan) mollusks from the upper unit of the Berclair terrace of Medio 

 Creek in Bee County. A summary of the previously known occur- 

 rences of these Pleistocene mollusks in Bee and San Patricio counties 

 is represented in Chart 1. The stratigraphic placement and abundance 

 of the snails in the upper unit of the Fordyce Quarry deposits are 

 shown in Chart 2. 



Armigerus obstructus, Bulimulus alternatus marine, Euconulus 

 cher sinus trochulus, and Helisoma tenue sinuosum are herein reported 



Chart 1. Distribution of Mollusks in the Pleistocene of Bee 

 and San Patricio Counties, Texas 



After Sellards, 

 1940, p. 1637 



Conkin and Conkin, 1962, 



p. 348, Bee County, Berclair 



terrace of Medio Creek 



Bee County, 

 undiffer- 

 entiated 

 Berclair 

 terrace of 

 Blanco Creek 



San Upper Unit Lower Unit 



Patricio ( post-Eunice ( Ingleside 



County Pleistocene ) correlative ) 



Bulimulus dealhatus 



X 





X 



X 







Helicina orbiculata tropica 



X 



X 



X 





Polygyra texasiana 



X 



X 



X 



X 



Praticolella berlandieriana 







X 



X 



Retinella indentata 







X 





Stenotrema leai aliciae 







X 









Stenotrema stenotrema 







X 















X 





Amnicola sp 







X 



X 



Helisoma antrosa 







X 





Helisoma trivolvis 



X 



X 



X 



X 











X 



X 













X 



Physa conoidea 



X 













X 







Physa integra 





X 







Amblena perplicata 







X 





Lampsilis hydiana 







X 





Pisidium sp 







X 







X 











X 









