/'A'/XC/PL/:S OF /^OCK WEATHERING 



86 1 



.WAI.VSKS ()!• KKKSH AND DECOMPOSED DIORITE. 



' A gain. 

 ANALYSES OF FRESH LIMESTONE AND ITS RESIDUAL CLAY. 



In reference to these analyses, it is advisable to make the 

 following statement : 



The Virginia gneiss, in the first table, in its fresh condition, as 

 analyzed, is a coarse, gray feldspar, a rich variety, with abundant 

 folia of black mica. 



Under the microscope it shows the presence of both potash 



