Accessories and Materials 



The following check list of materials and accessories is to aid in the 

 preparations for running samples. 



TABLE 3-1 



Inks — black, red, and blue (waterproof) . Colored Pencils 



Pencils— 2H, 4H, and 8H. (Mongol Indelible) 



Pen and holder— Hunt No. 104. Color Number 



Cloth pen wiper. Yellow 867 



Erasers— Pink Pearl, Ruby. Blue 845 



Plotting templet — to be made as shown in Red 866 



Figure 3-1. Green 848 



Artist charcoal-blending stumps Green — 888 



3/g in. dia. 6 in. length. Orange 862 



Sandpaper — No. and 1, for sharpening Brown 813 



stumps. Brown 853 



Magnet — small horseshoe. Purple 844 



Small knife. The last two digits are the number of the 



Steel teasing needle. color; the first is the pencil shape; i.e., 



Forceps — pointed, steel. numbers 767, 867, and 967 are the same 



Acid dish — glass furniture leg coaster. color. 



Scotch drafting tape. 



Dennison cloth tape (1% or 2 in.). Synthetic lacquer (model plane "dope"). 



1/2 millimeter grid. This grid can be made Lacquer thinner. 



by photographic reduction of millimeter Artist bristle brush — i/fc in., flat. 



cross-section paper. The grid is cemented Scoop tray — made from sheet aluminum as 



to the bottom of the scoop tray. shown in Figure 3-2. 



EXAMINATION OF The importance of accurate well-sample de- 



WELL SAMPLES termination and specific descriptions of the 



lithologies can hardly be over-emphasized. It 

 is basic geologic work — the foundation on which will rest the entire structure 

 of subsurface investigation. This structure, like any other, cannot be stronger 

 than its foundation. Microscopic sample determination is exacting", though not 

 exact. The materials with which the microscopist must work are subject to 

 differing interpretations, and it is invariably the careful and discerning worker 

 who will interpret correctly. The microscopist is very much on his own, and 

 the work of many others who use his logs depends on the reliability of his 

 determinations. As will be seen, many of his methods and tools are not precise, 

 and the accuracy of his work will depend largely on how well he applies them. 

 The geologist who runs samples should regard the lithologies he observes in the 

 light of his knowledge of the processes of sedimentation. He should frequently 

 ask himself how and why. Why was this kind of rock formed and how was it 

 formed? What were the physical, chemical, and biological conditions that 

 produced the rock? Many of the answers are evident in the chips from wells. 

 The geologist-microscopist is not merely a laboratory technician, unless, because 

 of his own lack of geological thinking and application, he reduces himself to 

 that status. He is first and last a geologist, and he is expected to do the work of 



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