SEDIMENTARY AND METAMORPHIC ROCKS 79 
most common mineral that resists disintegration, and 
therefore does not crumble to form clay; but there 
Fig. 31. 
A sand beach, Cape Ann, Mass. 
are also shell sands, magnetite sands, garnetiferous 
sands, ete. 
E7@.. 325 
A sandstone rock. 
