180 
Analyses of Books. 
divides the limestone range of the Sabine Hills from the principal trunk of the 
Apennines. Another chain of volcanic products seems to take off also from Ischia 
towards the Ponza group, through the islands of Ventotiene and San Stefano, main- 
taining a parallel direction with that first mentioned, and indeed with the general 
range of the escarpment of the elevated Apenniue strata, at the foot of which these 
explosions have found an issue.” 
“ It is certainly a remarkable confirmation of the opinion elsewhere expressed, 
as to the general parallelism of lines of volcanic eruption to the nearest linear 
ranges of elevated strata, that not only is there along the western coast of Italy this 
correspondence between two decided trains of volcanic vents, and the two parallel 
ranges of the Sabine mountains and the Apennines; but also, where a massive 
embranchment breaks off from the latter at nearly a right angle, forming the pro- 
montory which bounds the bay of Naples to the S. E. and the almost contiguous 
island of Capri, a corresponding line of volcanic vents (viz. that connecting Vesu- 
vius with Ischia) is found to take off from the principal line, at no great distance, 
and at the same angle, so as consequently to run parallel with the transverse elevat- 
ed range.” 
“ If we call to mind the general tendency of the rocks composing the secondary 
strata to yield to any disruptive force along fracture lines at right angles, or near- 
ly so, one to another, it. will appear highly credible that this parallelism, in two di- 
rections of the ranges of elevation and eruption, has been influenced here, as else- 
where, by that general, though at first sight, insignificant cause.” 
Mr. Scrope next enters into some detail to show, that the appearances at Monte 
Somma, which he considers a type of the volcanic structure, are not to be explained 
by the common opinion of the sides of the mountain having fallen in ; nor yet by 
that of which Von Buch, Dr. Daubeny, and Humboldt are the supporters, viz. of the 
whole mountain having been produced by tlie elevation of flat, strata on their edges 
round a central aperture by force of elastic gases. On the contrary be concludes, 
that all volcanic cones have been created by the repeated superposition of one vol- 
canic bed on another, all flowing from a central source ; a process which cannot 
fail to produce this peculiar form of hill. He contends in fact “ that the parallel and 
sloping beds which with a qmlqufiversal dip compose every such mountain, were 
not deposited horizontally or otherwise than at a high angle of inclination; and 
that the angular elevation they have since sustained is in general comparatively 
trifling : in short, that the conoidal form preserved by an habitual volcanic moun- 
tain in every stage of its formation, is owing to the same obvious cause which com- 
municates the similar figure to a simple volcanic hillock, the produce of a single 
eruption, viz. the accumulation of erupted matters round a central orifice. 
After giving a very full description of all the vents, extinct orignivomous, within 
the eircle intended to be described, Mr. Scrope adopts the conclusion, that “ this 
part at least, of tlie western coast of Italy has suffered an elevation of some hun- 
dred feet since the epoch of eruption of the greater number of volcanic mouths whose 
products wc have been employed iu examining, nud which are certainly much more 
recent than the tertiary or Subapenniue formation. In this elevation it is at least 
probable that the whole chain of the Apennines shared ; and indeed there are traces 
of it in the limestone cliffs of the Monte Circello and the Calabrian coast, which are 
in some parts thickly perforated by recent lithophagi at a height of more than a 
hundred feet from the present level of the sea.” 
“ W hether this elevation took place at once or by successive hearings accom- 
panying the earthquakes which have habitually atfccted the western Apennines, from 
Rome to Palermo, is a question which it requires further inquiries to elucidate. 
From my own observations I should he inclined to donbt that any sensible change 
has taken place in the relative level of the land and water round Naples since the 
Roman era, (the few facts which have been brought forward to support the idea of 
such change, being contradictory, and to be otherwise explained) ; and for this reason 
I should prefer the conclusion, that the rise of the plains of Campania from below 
the sea was produced by some convulsive crisis of subterraneous expansion, occa- 
sioned perhaps by the long obstruction of the superficial vents, — those natural safety 
valves that by their occasional activity at present, may be supposed to obviate the 
recurrence of such tremendous operations. 
XXIII. Supplementary Remarks on the Strata of the Oolitic Series and the rocks 
associated wtth them, in the Counties of Sutherland and Ross , and in the Hebrides- 
Roderick Impey Murchison, Esq. Sec. Geo. Soc. F. R. S. F. L. S. pp. 353 to 368. 
This paper is supplementary to one published in a former part of this volume, fo r 
want of which the details would not be either so intelligible or interesting. 
