CLARK: ON THE TRIASSIC BOULDER, &c. 
67 
a soft and friable character. I have endeavoured to obtain 
some local description of the rocks, but unsuccessfully. 160 
yards west of a bridge to the east was a fault, of about 10 
feet, the downthrow on the east ; this was visible on both 
sides, the excavations here being about 80 feet wide. Twenty 
feet to the east false-bedding was very apparent, accompanied 
b}' several minor faults and a bed of marly clay. These rocks 
had a very slight rise towards the bridge, where they were 
exposed to a depth of 15 or 20 feet; the ordinary red tint 
prevailed nearly everywhere. 
Lying upon them, to a thickness of from 5 to 10 feet at 
first, but reaching more than 25 feet at the bridge, was a 
bed of pebbles, the division between which and the subsoil 
— even in hollows where this reached a considerable thick- 
ness — was nowhere distinctly marked. These we thought 
must be recent, so closely did they resemble the numerous 
gravel deposits, exposed in all directions around Birming- 
ham, which almost invariably assume the deep-red Triassic 
tint. The pebbles were nearly all quartzitic, a few only 
appearing to be of igneous origin ; but these were generally 
much decomposed. Although coming out with ease to the 
hammer or pick-axe, there was more cohesiveness than is 
usual in recent beds, the angles in the cuttings standing out 
sharply. 
A suspicion was thus raised as to their origin, and further 
strengthened when, on turning westwards, we found exten- 
sive excavations in clayey gravel beds, lying in clays, but 
with lenticular sand-masses very like the rock we had 
previously examined. This suspicion was as much grounded, 
however, upon their position as upon any peculiarities. In 
general appearance the beds corresponded strangely with the 
rearranged glacial gravels, so well exposed in pits on both 
sides of the Ouse below York. Many pebbles were of con- 
siderable dimensions, passing indeed into small boulders ; on 
none were any ice-scratches visible. 
