U. S. GEOLOGICAL SURVEY 
BULLETIN NO. 324 PL. XLV 
FAILURE OF HOLLOW TERRA-COTTA TILE FIREPROOFING. 
A, First story of Spring Valley Water Company's Building, San Francisco (photograph by John Stephen Sewell); 
/;, Mills Building, San Francisco (photograph by Richard L. Humphrey). The lower webs of the floor tiles 
were spalled or taken entirely off by the fire. 
