CLAY, MARLE, AND SAND. 6] 1 



with other ingredients of less importance. The ferru- 

 ginous sand of the English strata. 



F. Quartz, limestone, mica, and green earth. 

 The green sand of the same series. 



These also are sometimes indurated into 

 sandstones which have been already enumerated 

 under that title for the convenience of the 

 reader. 



H K $ 



