DEPOSIT OF THE GRAUWACKE ROCKS. 65 
of the remaining rocks, and still more on the partial 
symptoms of gradation of animal forms observed in 
the fossiliferous part of these, we might be tempted 
to indulge in the notion of repeated catastrophes, 
but, as I have previously intimated, the facts related 
in support of the absolute connexion of the lime 
and slate,—lime and sandstone,—sandstone and 
slate, &c. together with the absolute inclusion of 
small patches of these deposits in their beds, forbid 
this supposition. We must then regard these rocks 
as one series, as coeval deposits—the results of one 
agency. But, though consecutive epochs have not 
been employed for their depesition, it is highly 
probable that the action was not altogether simul- 
taneous ; non-fossiliferous slate or schist may have 
been first precipitated, partly filling the interspaces 
of the granite, and connectedly therewith the fossili- 
ferous greywacké, siliceous and clay-slates; portions 
of schistose dunstone and compact greywacké also 
would occur ; while these were yet in a somewhat 
fluid state, and had not as yet assumed their final 
position, sandstones and limestones would be de- 
posited at intervals amidst these rocks, and their 
approximating fragments become blended, diffused 
and projected respectively one sort into another ; 
the sandstones might now acquire animal forms 
from their neighbours at the points of junction, and 
the limestone precipitate or fluid already charged 
with the forms of primeval creation nearly through 
its whole course would impart certain of those 
animals to the slates, and thus account for the 
similarity of these remains in the members of this 
series of rocks. ‘Those who consider trapp a 
“ transition rock” might say, that together with the 
sandstones and limestones, our trapp rocks (never 
however containing fossils) would assume their 
place in the general mass, and though the usual 
character of this formation and its freedom from 
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