U. S. GEOLOGICAL SURVEY BULLETIN 845 PLATE 8 
A. AUSTIN CHALK IN SAN PEDRO PARK, SAN ANTONIO, TEX 
The thick hard layer in the — consists largely of Gry phaea aucella, an oyster reef of Comanche 
time (Lower Cretaceous). (Stephenson.) 
ERN PART ¢ OF S SAN pei tate 
White caliche, 10 feet 1, 10 feet, and Midway shaly 
clay, rs ‘og "(Stephenson.) 
