Geological Society. 487 
clature ; whilst nearly all parties are in unison as to the fundamental 
fact of referring the slates of South Devon and Cornwall to the epoch 
of the old red sandstone formation. The term grauwacke, however, 
I rejoice to think, will not be condemned to the extirpation which 
has been threatened from the nomenclature of geology; it may still 
retain its place as a generic appellative, comprehending the entire 
transition series of the school of Freyberg, and divisible into three 
great subordinate formations:—the Devonian system of Sedgwick 
and Murchison being equivalent to the upper grauwacke, the Si- 
lurian to the middle grauwacke, and the Cambrian system to the 
lower. 
In this threefold distribution of the vast series of strata which 
have hitherto been indiscriminately designated by the common term 
grauwacke, we are, as it were, extending the progressive operations 
of a general inclosure act over the great common field of geology ; 
we propose a division, founded on measurements, surveys, and the 
study of organic remains, analogous to that of the secondary strata, 
from the chalk downwards to the coal formation, established by 
William Smith, and to the separations of the once undivided ter- 
ritory of the great tertiary system, effected by Cuvier and Brongniart, 
Desnoyers, Lyell, and Deshayes. 
To the uninitiated in geology, rectifications in the distribution 
of strata upon so large a scale may seem calculated to shake confi- 
dence in all the conclusions of our science ; but a contrary inference 
will be drawn by those who know that these corrections have never 
been applied to conclusions established on the sure foundation of 
organic remains, but to those rocks only of which the arrangement 
had been founded on the uncertain character of mineral compo- 
sition. 
' : FOSSIL VEGETABLES. 
Mr. Barber Beaumont, in a communication respecting these same 
trees, considers that no drifted plantsoccur in coal fields, and that 
all the vegetables which are now converted into coal, grew upon 
swampy islands covered with luxuriant vegetation, which accu- 
mulated in the manner of peat bogs; that these islands, having 
sunk beneath the sea, were there covered with sand, clay and shells, 
till they again became dry land, and that this operation was repeated 
in the formation of each bed of coal. In denying altogetherthe pre- 
sence of drifted plants, the opinion of the author seems erroneous ; 
universal negative propositions are in all cases dangerous, and more 
especially so in geology: that some of the trees which are found erect 
in the coal formation have not been drifted, is, I think, esta- 
blished on sufficient evidence; but there is equal evidence to show 
that other trees, and leaves innumerable which pervade the strata 
that alternate with the coal, have been removed by water to con- 
siderable distances from the spots on which they grew. Proofs are 
daily increasing in favour of both opinions: viz. that some of the 
vegetables which formed our beds of coal grew on the identical 
banks of sand and silt and mud, which being now indurated to 
stone and shale, form the strata that accompany the coal; whilst 
