LI ME ROCK. 
49 
slate is far from uncommon, the sandstone does also 
as I have reason to think, form with it an anomal¬ 
ous or bastard compound in one or two cases, 
besides alternating together distinctly. 
Although the ‘general * or prevailing order of oc¬ 
currence of our “ transition rocks,” counting from 
the granite and other igneous formations towards 
the coast, be such, that the limestone tract is inter¬ 
mediate to the slate northwards, and the sandstone 
on the south, yet, this rule laid down by many ex¬ 
perienced geologists, is reduced to an unscientific 
dogma by examination of the relations assumed by 
limestone, in its progress eastward, in which it will 
appear that this order is oftentimes reversed, and 
that limestone may have both other rocks north¬ 
wards, and both southwards of it; that in short this 
stratum considered in the mass, is to be regarded as 
mingled up in every possible way, with its associ¬ 
ated formations. 
The direction assumed by the limerock about 
Plymouth, and so far as Yealmbridge, is east and 
west, or rather, as observed by Mr. ELennah, it points 
a little towards north-west and south-east.* As 
regards its dip , it is about south-west, but this 
differs much, and in some spots, but little of this 
characteristic of stratified rocks, can be discerned ; 
oftentimes it is very steep, while at others, the rock 
is nearly horizontal in its bed, some of the lime at 
Deadman’s Bay, near Plymouth for instance. In 
general however, where uncertainty exists as to a 
block of limestone being artificially or naturally 
placed in the ground, the conjunction of these two 
characteristics in it, will for the most part enable a 
person to decide. The colours of the South Devon 
limestone are numerous, and though it is very ge¬ 
nerally grey with certain admixtures, it occurs often 
*“ Account ofthe Limerocks of Plymouth”by Rev, R. Hennali,F.G.s. 
H 
