PETROGRAPHIC CHARACTER OF OHIO SANDS 163 
seen that as more detailed work is done in the region of the crystal- 
line rocks, more and more of the ‘‘Complex”’ is differentiated and 
removed from the pre-Cambrian and proved to be more recent. 
Is it not possible that the general scarcity of garnet in the older 
sandstones may be due to the more recent formation of many 
garnetiferous schists which are now classed as pre-Cambrian ? 
