206 S. A. ADAMSON: THE SKIPTON AND ILKLEY RAILWAY. 



thought had also a special fitness for the section. The strata of the 

 earth's crust are sometimes disturbed and bent into folds ; the basins 

 or troughs of these undulations are called synclinals, the saddles or 

 ridges have the name of anticlinals. Now, in this quarry at 

 Draughton, within a distance of some 30 yards, the beds of limestone 

 bend, without breaking, into two sharp anticlinals, with corresponding 

 synclinals, that is, roughly speaking, in the shape of an inverted W ; 

 to give a better idea of the extent of this contortion, it may be stated 

 that these beds dip respectively, beginning at the left or north side 

 of the section, 60 degrees N.W., 52 degrees S.E., 75 degrees N.W., 

 and 10 degrees S.E. The rock thus bent is the mountain limestone, 

 very similar in composition to the Skipton Rock already named. As 

 Mr. J. E. Bedford has so concisely pointed out, there are three great 

 leading causes to account for this splendid example of contortion — 

 firstly, immense lateral pressure; secondly, the slow and very gradual 

 operation of the same ; and thirdly, the pressure during this crump- 

 ling of a vast thickness of overlying strata, since removed by 

 denudation. These causes have brought about what we here see — 

 the hard limestone, originally horizontal, bent without breaking into 

 these sharp folds in so short a distance like so much paper. On the 

 north side of the quarry was observed a splendid example of 

 ^ slickensides,' or the smooth surface of one side of a fissure, caused 

 by friction ; it was finely polished, and the groovings or striae were 

 remarkably distinct. A little way from this section a hurried glance 

 was taken of the Wheelam Rock Quarry, where is another fine 

 example of contorted limestone beds. The limestone here has a dip 

 of 65 degrees S.S.E., but inside the quarry the beds tilt up again, and 

 •form a striking example of a synclinal or trough. The railway was 

 again resumed, and an embankment traversed, about 1,000 yards in 

 length, under which was found, in foundations for bridges and 

 culverts, hard black and brown shales. A short walk brought the 

 party to a point where the line passes through the lower side of a 

 quarry, belonging to the Duke of Devonshire, and worked for lime- 

 stone, this being used for road metal, and also some being burnt for 

 agricultural purposes. This quarry, known as the Hambleton Rock, 

 is famous for presenting, on a majestic scale, evidence of the great 

 geological disturbance already referred to. Here again, the mountain 

 limestone, originally laid down in deep and tranquil water in a fairly 

 horizontal position, has been contorted in a most extraordinary 

 manner. On the eastern side of the quarry could be seen the various 

 beds of shale and limestone (which were very distinctly laminated) 

 dipping to the N.W. at an angle of about 40 degrees, then turning 

 at a sharp angle and becoming vertical. The beds were seen to 



Naturalist, 



