DIRECTIONS FOR COLLECTING ROCKS AND FOR THE 

 PREPARATION OF THIN SECTIONS. 



By George P. Merrill, 

 Curator of the Department of Geology. 



PART I. — DIRECTIONS POR COLLECTING ROCKS. 



Tig. 1. Fig. 2. 



Collecting hammers. 



Eock collecting differs 

 from that employed in other 

 branches of natural history 

 mainly in the simplicity of 

 the process. 



TOOLS EMPLOYED. 



For purposes of field 

 work, and when the col- 

 lector is obliged to carry 

 his entire outfit on his per- 

 son or attached to the sad- 

 dle, but two hammers are 

 usually employed, the one 

 a square-faced implement 

 of about 2 pounds weight, 

 with the ijeaii (also sx)elled 

 peen) in a directiou parallel 

 with the handle. The pro- 

 l^ortious found most satis- 

 factory are, head, 5 inches 

 in lengtli; face, 1^ inches 

 square, and handle, some 



Tig. 3. 

 Chisel. 



13 inches in length. This hammer (fig. 1) is used for separating the 

 specimens from the parent mass. 

 [3] 



