PART II. 



Geology. 



CHAPTER III, 



STRUCTURE. 



Description of Terms. 



Geologic structure, which is that branch of geology treat- 

 ing of the pitch of the stratified rocks, has been discussed at 

 length in previous Reports of the Survey. Since these Reports 

 are available, the discussion will not be repeated here, but the 

 following paragraph, taken from a former Report, 1 gives a 

 definite idea of simple scientific terms that will benefit the 

 general reader : 



"In the discussion of these structural forms on subsequent pages, 

 the upward bending arch is known as an anticline; the downward 

 bending trough, a syncline; the line joining the highest points of an 

 anticline or the lowest points of a syncline, the axis of the fold; the 

 direction of the horizontal edges of dipping strata, the strike; and the 

 structural form resulting from the sudden rise or fall of the axis of an 

 anticline, the nose of the fold." 



Method of Representing Structure. 



The contour method of representing structure has been, 

 used in the Lewis and Gilmer area. By this method of repre- 

 sentation, a single coal bed or other prominent and easily 



l Ray V. Hennen, Monongalia-Marion-Taylor Report, W. Va. Geol. 

 Survey, p. 76; 1913. 



