724 



ARTHUR C. TROWBRIDGE 



east of Alvord. In this re-entrant, are a series of unconsolidated 

 and partly consolidated sands, clays, and gravels. They were 

 traced from wall to wall of the re-entrant, and up the canyon for 

 some 3^ miles. Mr. Walcott reports their continuation almost to 

 the. crest of the mountains. 



There are two more or less distinct phases of this deposit. Near 

 the north and south walls of the re-entrant are interbedded clays, 

 limestones, and conglomerates. These materials are mostly sorted 

 into distinct beds, but are locally arranged in pockets or irregular 





Fig. 14. — Lacustrine limestones and conglomerates, deposited near shore in the 

 Waucobi embayment. 



areas, when seen in sections. Two miles east by northeast of Alvord, 

 a ledge of limestone and conglomerate outcrops under a low hill 

 of angular alluvium. The limestone is white, porous, earthy, and 

 filled with small fossils of gastropods. Other rock has a matrix of 

 calcium carbonate, but contains enough pebbles to make it conglom- 

 eratic, though the pebbles are seldom in contact. The stony matter 

 is fairly well rounded. In size its pieces reach 6 in. in diameter, 

 though the average is about 1 in. The pebbles are mostly of sedi- 

 mentary rock, but with some granites. All the material is local. 



A series of exposures along the main road 1^ miles southeast 

 of the fruit ranch of J. S. Graham, at the southeast margin of the 

 re-entrant, shows well the constitution of the beds. All the mate- 

 rial is irregularly sorted. In some places it is of light-yellowish 



