Strata in the Brook Pulcovca . 
389 
strata as those at A .) to have disappeared without the presence of the 
dark green clay. However, on taking a bird’s eye view from the 
heights, there appears ample room between the spot where the 
alluvium first obstructs our sight of the limestone, at e and f, and 
the point L, where it terminates, and exposes the blue clay, to allow 
of a sudden turning up of the limestone, and subjacent dark clay 
within the heart of the cliff, which presents on the outside nothing 
but alluvial debris ; were the cliff higher, it might perhaps have 
been seen. To prove that this is not entirely conjecture, it may be 
stated that on the side of the opposite hill, at d , the superficial soil 
shews some signs of the dark clay, and though this alone might not 
be sufficient, yet it must be allowed to have some weight, when it is 
repeated a little further on (and at a greater elevation, which implies 
strata rising to the E.) and of less doubtful appearance at b. But to 
confirm this, there luckily lies immediately below in the bed of 
the river, a very large mass of the dark clay, in its most character- 
istic form, which has evidently been detached from the hollow, in 
which are seen the traces of it at b : and to put out of all doubt the 
fact of the strata having been turned up, and that they are now 
gradually disappearing (as they ought) to the east above the blue clay, 
there appear at a still higher level, c, near the top of the hill, 0 , a 
clayey variety of the lower beds of the limestone, exhibiting all its 
characteristic colours, and which probably does not extend much 
further east. It may exist under the hill JP, but the accumulation or 
gravel is too great to allow of any thing being seen on that side. 
In taking a comprehensive view of this interesting portion of 
country, w r e perceive that it must be considered as an insulated 
portion of the great Doodorof limestone ; differing indeed from 
most outliers, in not forming a high cap or insulated hummock, 
but rather a mass which appears sunk or half buried in the blue 
