56 Geological Society. 



and inverted, having the tibia and fibula lying next to the pelvis ; 

 the other sacral extremity appears to be concealed by the broad 

 bones of the pubis. The author has given as full an account of 

 all the bones of this interesting animal as the hardness of the im- 

 bedding rock, or the safety of the specimen, would allow of their 

 examination. 



A letter was then read, addressed to the President and Fellows 

 of this Society, " On the ancient and present state of Vesuvius," 

 by Count de Montlosier, For. Mem. G.S. President of theAcademy 

 of Clermont Ferrard, S:c. &c. 



The author offers this short notice on Mount Vesuvius in testi- 

 mony of the grateful sense entertained by him of having been 

 elected Foreign Member of the Geological Society; and the present 

 communication is intended to convey his opinions, formed during 

 a visit to Naples in the year 1813, in respect to the age and origin 

 of Mount Vesuvius, and of its neighbour Monte Somma. 



Having pointed out the direct analogy between the active vol- 

 cano of Vesuvius, and the extinct volcanoes of Auvergne, formerly 

 described by him, Count Montlosier proceeds to show that the 

 Monte Somma is the true Vesuvius of the ancients, the present 

 volcano being of posterior formation; and he arrives at this conclu- 

 sion by various considerations upon the nature and form of Somma, 

 which he supposes to be the remaining segment of a vast elliptical 

 cavity, the other sides of which have since been destroyed. The 

 chief object of the author, however, is to point out the very dif- 

 ferent origin of such a large crateriform hollow as that of the ancient 

 Vesuvius or Somma, which he attributes to explosions, and the small 

 crater of the present Vesuvius, which gives vent to currents of 

 lava. The former having destroyed the towns of Pompeii and Stabise, 

 with showers of puzzolana and ashes, the latter having overflowed 

 Herculaneum. He endeavours to strengthen this theory by reference 

 to a peculiar class of extinct craters in the Eyfel, in Central France, 

 and in the Phlegroean fields; the circular hollows of which have since 

 been occupied by small lakes usually of great depth. As none of 

 these have lava-currents issuing from them, and many of them are 

 devoid of marks of igneous alteration, they are considered by the 

 author to be of the same origin as the ancient Vesuvius, i. e. craters 

 formed by sudden explosion. 



Strabo, Pliny, and Dionysius of Halicarnassus, are quoted in proof 

 of the ancient Vesuvius having had the outline of only one moun- 

 tain ; and it is stated that an antique painting, recently discovered 

 at Pompeii, represented the same fact. 



The notice was accompanied by drawings of the supposed form 

 of the Vesuvius of antiquity, before the great eruption under Titus ; 

 of the condition of the mountain after that catastrophe, by which 

 it is presumed that its summit was destroyed and blown away in 

 6?driVzi5 and puzzolana, leaving an enormous crater; and lastly, of 

 the Jinnl state of the mountain, presenting three sides of the an- 

 cient area broken down, with a parasitic cone and crater established 

 on its flank. 



Nov. 



