Geology of England and Wales, &c.” 233 
iwansition) corals, encrinites, and testacea, different how- 
ever from those now known, appear at first sparingly ; the 
fossil remains of the carboniferous limestone are nearly of 
the same nature with those in the transition rocks, but 
more abundant ; the coal measures, however, themselves, 
which repose on this limestone, scarcely present a single 
shell or coral ; but on the contrary abound with vegetable 
remains, ferns, flags,reeds of unknown species, and large 
trunks of succulent plants, strangers to the present globe. 
Upon the coal rest beds again containing marine remains 
(the magnesian limestone) ; then a long interval (of new 
red sandstone) intervenes, destitute almost, if not entirely, 
of organic remains, preparing as it were the way fora new 
order of things. This order commences in the lias, and is 
continued in the Oolites, green, and iron sands, and chalk. 
All these beds contain corals, encrinites, echinites, crusta- 
cea, testacea, vertebral fishes, and marine oviparous quad- 
rupeds, yet widely distinguished from the families contained 
in the lower beds of the transition and carboniferous class, 
and partially distinguished among themselves according to 
the bed which they occupy. Hitherto the remains are al- 
Ways petrified (i.e. impregnated with the mineral substance 
in which they are imbedded ;) but lastly, in the strata 
which cover the chalk we find the shells merely preserved, 
and in such a state, that when the clay or sand in whic 
they lie is washed off, they might appear to be recent, had 
they not lost their colour and become more brittle. Here 
We find beds of marine shells alternating swith others pecul- 
iar to fresh water, so that they seem to have been deposit- 
ed by reciprocating inundations of fresh and salt water. In 
Coast ; and lastly, over all these strata, indiscriminately, 
P- 11, Introd. 
Vou. VII.—No. 2. 30 
