92 
whole of our existing knowledge of the relations of fossiliferous beds 
of limestone. 
GEOLOGICAL DYNAMICS. 
In that part of geology which I have termed Geological Dynamics, 
and which investigates and applies those causes of change by which 
we may hope to explain geological phenomena, we may still observe 
that fundamental antithesis of opinion which has long existed on the 
subject ;—the division of our geological speculators into Catastro- 
phaists and Uniformitarians ;—into those who read in the rocks of the 
globe the evidence of vast revolutions, of an order different from 
any which those of man has survived ;—and those who see in the con- 
dition of the earth the result of a series of changes which are still 
going on without decay, the same powers which produced the ex~ 
isting vallies and mountains being yet at work about us. Both these 
opinions have received their contributions during the preceding 
year: Mr. Darwin having laid before us his views of the formation 
of mountain chains and volcanos, which he conceives to be the effect 
of a gradual, small, and occasional elevation of continental masses 
of the earth’s crust; while Mr. Murchison gathers from the re- 
searches in which he has been engaged, the belief of a former state 
of paroxysmal turbulence, of much deeper rooted intensity and wider 
range than any that are to be found in our own period; and M. de 
Beaumont, in France, has endeavoured to prove that Etna and many 
other mountains must have been produced by some gigantic and ex- 
traordinary convulsion of the earth. Both Mr. Darwin and M. de 
Beaumont refer to the same examples; and while M. de Beaumont 
conceives that the cones of the Andes must have been formed by an 
~ abrupt elevation, caused by subterranean force, Mr. Darwin has 
maintained the opinion, that these lofty summits have been gra- 
dually tlirust into the place which they occupy by a series of suc- 
cessive injections of molten matter from below, each intruded por- 
tion of fluid having time to harden into rock before it was burst | 
and again injected by the next molten mass. For how otherwise, 
he asks, can we conceive the strata to be thrust into a vertical po- 
sition by a liquid from below, without the very bowels of the earth 
gushing out? Without attempting to answer this question, we may 
observe, that when we suppose, as Mr. Darwin supposes, a vast por- 
