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sinking of the vaulted roof of the cavern or caverns, now occupied, or filled up in part, by thelake itself From these various circumstances, it may certainly be inferred, that there was a timewhen the strata of the Saleve extended or projected much more towards the north-west than atpresent, as the perpendicular chamfretings, and the irregular forms so conspicuous on the sameside, clearly evince, as well as the enormous stones, or rather immense rocks, now seen lying atits foot, resting against its basis to a considerable height, which in many parts even exceed onethousand feet. The thickness of these rocks, their structure, their direction, and the differentspecies of fossils therein imbedded, &c. tend still further to show that they doubtless, at one time,not only formed a part of the same mountain, but likewise even a part of the vaulted roof whichcovered the cavern or caverns: for there is every reason to believe, from the calcareous matterfound in their vicinity, as also from the white sand-stone, with calcareous cement, lying in differentplaces at their basis, composed of the same species of white sand found on the summit of theSaleve , in strata of two or three feet thickness, that the rocks which now appear as though shooting-out of the ground, and resting against its basis, are a small part of the total mass only, the resthaving since been covered, or entirely buried, by fragments of the same mountain and successivesediments of the sea.

Finally, there can remain no doubt of the great revolutions and commotions of Nature expe-rienced in that mountain at a date much anterior to the one which has given it the form it nowhas, if those parts contiguous to the villages of Collonge and Le Coin be attentively examined.There immense fragments, formed by a number of huge rocks, are conspicuous, which, by theirmass, literally appear like small or lesser mountains, placed at the basis of the Salfeve: many ofthem, which are of a pyramidical figure, are upwards of three hundred feet in height. But whatappears more surprising, and again more forcibly corroborates my idea of the severing or breakingof the mountain, is the wide and deep fissures which exist in that part of the Saleve , and reachfrom the top to the bottom, with an opening of nearly from two to three feet at their entrance,besides caverns, which apparently extend far into the interior of the mountain,—among which arethose of Balme and Orjobet: in short, the perpendicular pits, and many other objects similar tothese, equally curious and interesting to the lithologist, not only prove the effects and havoc ofsome violent debacle, but likewise those of an impetuous current, whose direction tended fromnorth-north-east to south-south-west.

If the Sal&ve be considered as abounding with curious and singular appearances, the Jura mayalso be deemed no less deserving of notice, as must clearly have appeared when speaking of theDole; therefore, that I may not enlarge too much on a similar subject, I shall briefly mentionwhat will be most necessary to support my hypothesis,—I shall confine myself to describing thedirection ofits strata, which are invariably so inclined on the side next the lake, as well as towardsthe north-north-western, that if it were possible to see or examine the section of the mountainitself, those same strata, which almost touch at the summit, would be found resting on the nucleusof the mountain, diverging so considerably as to form a true Greek lambda (A), the top of whichrrotild very nearly represent the summit of the Jura .

' It may however be proper to remind my reader, that I mean to be understood as speaking onlyin general terms of the strata of that mountain, having before noticed that it would be impossibleto enter into a minute detail on the subject, owing to the great irregularity and heterogeneity ofthe mass. But as the nucleus of the Jura is visibly of the secondary class, although of calcareousspecies, the strata above mentioned may be considered in great part of the tertiary, from theircontaining fossils. It is consequently my firm opinion, that they doubtless are of posterior dateto the formation of the neucleus, and that they cannot have taken their present direction, unlessby some great operation of Nature , which, from their original horizontal surface, has forced them,by some sudden sinking of the earth, to become as inclined as 1 they now appear. Hence I havealso been led to infer, from the extreme irregularity and confusion in their direction, which insome places exhibits vertical forms, and in other, zig-zags, and sometimes seems even to describea portion of a circle,—as likewise from the caverns found in the interior of the mountain, the cal-careous matter which in many places covers the summits of the Jura , as well as the monticules,or small hills, on its sides and basis, that several of these strata at one time communicated withthose of the Saleve , and that, from every appearance, the change in their original direction to thepresent may be reasonably presumed to have happened at the epoch when the sudden crush, whether

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