514 PKOCEEDINGS OF THE GEOLOGICAL SOCIETY. [Feb. 2, 



They, as I have just shown, insist upon the entire volcanic moun- 

 tain, just as we now see it, having sprung out of the ground at one 

 jump — blown up suddenly, like a bladder, by a single effort, — the 

 whole amount of inclination exhibited by its outer slopes, or by its 

 component beds, being the result exclusively of the sudden and simul- 

 taneous ^' swelling up " of its entire mass of beds from a previously 

 horizontal, or nearly horizontal, position. 



The extracts I have given from their works place this beyond 

 dispute. 



But, indeed, this doctrine, in its extremest sense, is a necessary 

 consequence of the argument on which it is based by the Upheaval- 

 ists, namely, the asserted impossibility (said to have been demon- 

 strated by the observations of M. Elie de Beaumont on Etna) that 

 any bed of lava, other than a mere scoriform strip, or string, or thin 

 crust, has or could have consolidated at an angle of slope exceeding 

 2° or 3°, or at the very outside 5°. This is an argument which, as 

 has been justly observed by Sir Charles Lyell (in the last edition of 

 his ' Manual ', p. 507), applies, of course, to the very uppermost bed 

 of lava to be found upon the slope or in the framework of a vol- 

 canic cone, quite as much as to any of those beneath it. If, then, 

 the law laid down by M. de Beaumont is a true one, every cone or 

 volcanic mountain upon or near whose external surface any solid 

 bed of lava occurs having a greater inchnation than 3° or 5° (a de- 

 scription which includes probably all the known volcanic mountains 

 in the world) must have been upheaved entirely, as we now see it, 

 from a nearly horizontal position since the deposition of that upper or 

 most recent lava-stream. 



I shall presently advert to the baseless character of the assumed 

 law as to the non-consohdation of lava upon steeper slopes than 3° 

 or 5°, laid down by M. de Beaumont. 



Meantime, the question being thus cleared from all ambiguity, 

 the first remark that suggests itself is, that the upheaval- theory abso- 

 lutely ignores all volcanic eruptions whatever from the central vent 

 of a volcanic mountain subsequent to its original creation (or rather, 

 according to their notion, of its inflation) — at least as having erupted 

 anything beyond gases and a sprinkling, perhaps, of ashes. In 

 fact, in i^his view, volcanic mountains exist independently alto- 

 gether of volcanic eruptions, and might, nay, would, be just what 

 they are, even though they had never been in eruption at all*. 

 Of course, the fact of eruptive phenomena having repeatedly taken 

 place from such mountains, even within historic and recent times — 

 eruptions of intense violence, and which threw up, often through 

 long periods, prodigious quantities of fragmentary materials, and 

 poured forth from the central vents or their immediate vicinity 

 abundant streams of lava, — could not be altogether denied. M. de 

 Humboldt, indeed, in some passages would appear by no means to 



* Indeed, de Buch expressly says of the basaltic (doleritic) beds that com- 

 pose the bulk of Etna, referring to those seen in the escarpments of the Val del 

 Bove, " These beds derive their origin from phenomena anterior to the action of 

 the volcano itself." — Canaries (Paris edit.), p. 328. 



