234 Geological Society : — Anniversary of 1S39. 



almost the whole of our existing knowledge of the relations of 

 fossiliferous beds of limestone. 



In that part of geology which I have termed Geological Dyna- 

 mics, and which investigates and applies those causes of change 

 by which we may hope to explain geological phenomenaj we may 

 still observe that fundamental antithesis of opinion which has 

 long existed on the subject ; — the division of our geological spec- 

 ulators into Catastrophists and Unifor7nitarict7is ; — into those 



who read in the rocks of the fflobe the evidence of vast revolu- 



tions, of an order different from any which those of man has sur- 

 vived ; — and those who see in the condition of the earth the re- 

 sult of a series of changes which are still going on without decay, 

 the same powers which produced the existing valleys and mount- 

 ains being yet at work about us. Both these opinions have re- 

 ceived their contributions during the preceding year : Mr. Darwm 

 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 endeavored to prove that 

 Etna and many other mountains must have been produced by 



some gigantic and extraordinary 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 subter- 

 ranean force, Mr. Darwin has maintained the opinion, that these 

 lofty summits have been gradually thrust into the place which 

 they occupy by a series of successive injections of molten matter 

 from below, each intruded portion of fluid having time to harden 

 into rock before it was burst and again injected by the next mol- 

 ten mass. For how otherwise, he asks, can we conceive the 

 strata to be thrust into a vertical position by a liquid from below, 

 without the very bowels of the earth gushing out? Without 



answ 



* An abstract of Mr. Darwin's paper was given in L. and E. Phil. Mag., voK 



xiij p. 584. 



