60 Geological Sociely. 



canic focus burst out within the area of the lacustrine deposits, it is 

 stated that limestone and marls occur near Murat at the foot of the 

 Eastern watershed of the highest ranges of the Cantal, where beds 

 extensively quarried for lime, and containing several species of Lim- 

 neus, Planorbis, Bulinus terebra, &c. with gyrogonites and plants; 

 are overlaid by a prodigious accumulation of volcanic products. The 

 fresh-water strata at this locality (La Vissiere) are unaltered in their 

 character, but exhibit many faults. 



The organic remains found in different parts of the Cantal, prove 

 that this lacustrine formation, although geographically separated from, 

 is geologically of the same age with that of the Limagne d' Auvergne, 

 and corresponds as a whole to the different divisions of the fresh-water 

 strata of Paris, and those of HordwcU Cliff and the Isle of Wight in 

 England. It is more difficult to obtain an accurate knowledge of all 

 the strata in the Cantal, than in the contiguous regions of Mont Dor, 

 Clermont, &c. For in the last-mentioned districts, the volcanoes had 

 issue amidst the primary rocks, their lava currents only reaching to 

 the outskirts of the lacustrine formations 5 whereas those of the Cantal 

 burst out in the very centre of these tertiary deposits, and either 

 buried them or produced changes of the relative levels of the country, 

 80 as to occasion much abrasion of the original strata by the frequent 

 shifting of the direction of the waters. 



In conclusion, a comparison is instituted between the lower members 

 of the lacustrine deposits of the Cantal, and those of the Limagne 

 d'Auvergne and of the Puy en Velay. 



A paper by Dr. Bucklan'd was read, stating that he has ascertained 

 that the bony rings of the suckers of cuttle-fish are frequently mixt 

 with the scales of various fish, and the bones of fish, and of small Ich- 

 thyosauri in the bezoar-shaped faeces from the lias at Lyme Regis. 

 These rings and scales have passed undigested through the intestines 

 of the Ichthyosauri. Dr. Prout has also found that the black varieties 

 of these bezoarsowe their colour to matter of the same nature with the 

 fossil ink bags in the lias ; hence it appears that the Ichthyosauri fed 

 largely upon the sepiae of those ancient seas. 



The author has also ascertained, by the assistance of Mr. Miller 

 and Dr. Prout, that the small black rounded bodies of various shapes, 

 and having a polished surface, which occur mixt with bones in the 

 lowest strata of the lias on the banks of the Severn, near Bristol, are 

 also of faecal origin : — they appear to be co-extensive with this bone 

 bed, and occur at many and distant localities. He has also re- 

 ceived from Mr. Miller similar small black faecal balls from a calca- 

 reous bed neariy at the bottom of the carboniferous linfestone at 

 Bristol } this bed abounds with teeth of sharks, and bones, and teeth 

 and spines of other fishes : until they can be referred to their respective 

 animals, the author proposes the name of Nigrum Graecum for all these 

 black varieties of fossil feeces. They may have been derived from small 

 reptiles or from fish, and in the case of the lias bone bed, from the 

 molluscous inhabitants of fossil nautili and ammonites, and belemnites. 

 In a collection at Lyme Regis there is a fossil fish from the lias, which 

 has a ball of Nigrum Grsecum within its body ; for this the author pro- 

 poses 



