154 Mr Poulett Scrope's observations on the Volcanic 



At no great distance to the east of Ormont, the transition 

 rocks are concealed by strata of red sandstone, inclined at a 

 high angle, with an easterly dip. At the village of Steffler, 

 these are in turn covered by other sandstone strata, which ap- 

 pear to belong to the quader-sandstone : resting upon these, to 

 the S. of the village, rises a volcanic cone, composed of sco- 

 riae and puzzolana, partly incoherent, partly compacted into 

 a peperino. Steffler is built on strata of this latter kind, 

 which, however, by their inclination, are proved to have been 

 deposited by an eluvial torrent descending from another hill 

 N. E. of the village, which still exhibits a large circular cra- 

 ter on its summit. 



To the S. E. of Steffler, lies a small maar, or crater-lake, 

 which has been once drained, and since filled again by a dam 

 thrown across the channel of discharge, on which a mill is si- 

 tuated. 



The village of Roth is built on a current of basalt deriv- 

 ing from the cone which rises above it, and which has also 

 emitted a considerable mass of lava towards the north and 

 west. A small cavern, the mouth of a deep fissure in one of 

 these lava-currents, half-way up the side of the cone, is noted 

 for exhibiting a phenomenon, which I have met with else- 

 where, in many instances, amongst volcanic formations. The 

 floor of this grotto was paved with a thick crust of ice, when 

 I visited it at noon on a very hot day at the latter end of A u- 

 gust. During the summer, the peasants of the neighbour- 

 hood say it is always found there, while in the winter there is 

 none ; but, on the contrary, that the shepherds creep into the 

 cavern for warmth. The following appears to me the most 

 plausible mode of accounting for this curious fact : The cave 

 is probably the mouth of one of those arched galleries which 

 are so frequently met with under currents of lava in Iceland, 

 Bourbon, and elsewhere. If the other extremity of the gal- 

 lery communicates with the open air at a much lower level, 

 for instance at the foot of the cone, or where the lava stream 

 terminates in the plain below, a current of air must be con- 

 tinually driven through this passage from the lower to the 

 upper extremity. In its passage, it would be thoroughly 

 dried from the absorbent nature of the rock, (which is perhaps 



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