182 



Subsurface Geologic Methods 



complete studies three sections each normal to the other should be cut 

 from a specimen. It is also an excellent idea to polish the surface of the 

 specimen from which each section was originally sawed and to study 

 these under the microscope. If the data obtained from these studies are 



JKe-'aAJ 



Figure 75. Photomicrographs of thin sections from four sandstones of Morrison 

 formation near Golden, Colorado, illustrating morphological differences. Note 

 chalcedonic cementation in upper right. 



recorded on a block diagram, any directional variation in space relation- 

 ships shows up more readily. 



