CLARK: ON THE TRIASSIC BOULDER, &c. 
69 
signs of several faults, the positions did not exactly coincide. 
On both sides, probably, but very plainly on the south side, 
they were terminated 16 feet from the thick sands bya 
parallel fault, which seemed to bring up the same beds as 
those to the west. When once discovered, a fault was easily 
followed, even if invisible to the eye, from the remarkable 
effect produced upon the pebbles. This we soon noticed 
ourselves, and a " ganger," passing by, asked if we could 
explain how it was so many of the pebbles were " burnt." 
Although excessively hard, where unchanged, for a few 
inches on either side of faults the pebbles were perfectly 
rotten, a slight blow breaking them to pieces, or even reduc- 
ing them to powder. Was this induced by intense strain, 
implying the presence of enormous superincumbent deposits ; 
or can it be accounted for simply by weathering agencies, 
acting along the faults ? If the latter, why are not loose 
glacial gravels entirely reduced to this condition I If suffi- 
cient time has not elapsed, then it follows that these beds 
are not so recent ; but if, as seems more likely, it is due to 
intense strain, the same conclusion is pointed to, as necessary 
to produce the required cause. 
On proceeding, we found that this system of faults was 
but the first of a continuous series, extending to the very 
end of the cutting, which is, I believe, about half a mile long. 
Although the displacement varied from a few inches to a few 
yards, the general level of the beds changed little. This was 
clearly shown by a sandbed, like the thin beds already men- 
tioned, having an average elevation of four or five feet, which 
it soon regained even when considerably displaced. The 
faults were seldom more than four or five yards apart, often 
much less ; most ran nearly north and south, but a remark- 
able exception near the end, where a gravel bed ended off 
among sands, ran nearly east and west, the opposite section 
appearing many yards further on. Occasionally clay appeared 
among the pebbles, which invariably proved to be " burnt " 
