68 OUR LIMEROCKS NOT CORAL FORMATIONS, 
10. Not only do the strata occur often in discon¬ 
nected beds, but these beds themselves in the 
instance of each of the three rocks, are also com¬ 
pounded of assembled smaller ones aggregated 
without palpable separation. 
11. The surface of the country altogether presents 
an uniform rule in respect of the arrangement of the 
hills, and in general of their heights,—the slopes 
and curvatures of these whatever their compositions 
are not abrupt or broken; towards the lime tract 
also the slate hills become lower, as if to accommo¬ 
date themselves to the elevation of the former rock, 
and are gradually interwoven with it in the general 
surface of the country. 
A lecturer at the Plymouth Institution, as also a 
writer in the Geolog. Trans, have endeavoured to 
shew that our limestones are the formation of coral 
insects residing in a supposed ancient sea or basin, 
having the slates and sandstones for its bottom.* 
Now, allowing the above statements to act as nega¬ 
tive proofs against this notion, the following may 
be here introduced as positive proofs of its fallacy. 
Coral rocks such as are now forming, are of a loose 
and cavernous texture, of an uniform colour, exhibit 
clearly the habitations of the architects, are without 
stratification, dip, or absolute course. Our lime 
rocks are dense in structure, variable in colour, 
rarely present the traces of polypifers , have gener¬ 
ally decided stratification, dip, and course, conform 
* This idea was not novel, for even Buffon argued against the 
supposition—adducing the fact of stratification as decisive on 
the point, (see De Luc’s Travels in England) So far as respects 
the identity of the deposit of lime and slate, my own notion of 
coeval precipitation is not new, (see Moore’s Devon) but I am 
not sensible that any one has hitherto conceived the probable 
coeval deposit of the three fossiliferous rocks. 
