OBJECTS, DEVELOPMENT, AND RESULTS OF THE WORK OF 
COLLECTING WELL RECORDS AND SAMPLES. 
By Myron L. Fuller. 
The information relating to borings must generally be gathered 
when the well is being sunk or not at all. Many drillers keep records 
when the work is going on, but in the majority of cases these are soon 
lost. If the driller continues work in a single locality he soon comes 
to know perfectly the main points of the succession of the rocks and 
keeps no records, often even throwing away his earlier ones. In 
other cases he may remove to other regions, and, having no further 
personal interest in the original locality, the early records are lost ol- 
dest royed. Only the larger operators keep permanent records of their 
wells. For these reasons the effort is now being made by the Survey 
to secure the record at the time of drilling and to supplement it where- 
ever possible by actual samples, which will be filed and made perma- 
nently accessible for use whenever questions arise regarding the mate- 
rials encountered. 
IMPORTANCE OF ACCURATE WELL RECORDS. 
The knowledge of conditions beneath the surface, whether sought 
by the driller, the mining engineer, or the geologist, must be obtained 
either from surface observations of rock outcrops or from artificial 
sections afforded by mine or other shafts, inclines, tunnels, and borings. 
By systematic observations upon the character of the rocks over 
extended areas and the determinations of their inclination (dip) and 
their line of outcrop on level surfaces (strike), the trained observer is 
able to calculate more or less accurately the thickness of the beds, 
their depth below the surface, their structure, and to a certain extent 
their character as regards the occurrence of gas, oil, brine, or fresh 
wiiler. especially the latter. The thickness and composition of rocks, 
even of the same bed, are not constant, but undergo changes, often 
considerable in amount and taking place within short distances. These 
changes are frequently of great importance in their effect upon the 
occurrence of the products named. Where the rocks are at the surface 
the changes can be easily recognized, but when below the surface only 
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