^BB Natural History in London. 



been usually considered as derived from birds, ought to be attributed to 

 this extraordinary family of flying reptiles : Dr. Buckland is now in- 

 clined to adopt this opinion, and is disposed to think still further, that the 

 coleopterous insects, whose elytra occur in the Stonesfield slate, may have 

 formed the food of those insectivorous Pterodactyles. He conceives also, 

 that many of the bones from Tilgate Forest, hitherto referred to birds, 

 may belong to this extinct family of anomalous reptiles : and, from its 

 presence in these various locaUties, he infers that the genus Pterodactyle 

 was in existence throughout the entire period of the deposition of the 

 great Jura-limestone formation, from the lias to the chalk; expressing 

 doubts as to the occurrence of any remains of birds before the commence- 

 ment of the tertiary strata. 



2. Fossil Fceces of the Ichthyosaurus. The author concludes, from an 

 extensive series of specimens, that the fossils, locally called bezoar stones, 

 that abound at Lyme, in the same beds of lias with the bones of Ichthyo- 

 saurus, are the faeces of that animal. In variety of size and form they 

 resemble elongated pebbles or kidney potatoes, varying generally from 2 

 to 4 in. in length, and from 1 to 2 in. in diameter; some few being larger, 

 others much smaller : — their colour is dark grey ; their substance, like 

 indurated clay, of a compact earthy texture, and their chemical analysis 

 approaches to that of album graecum. Undigested bones and scales of 

 fishes occur abundantly in these faecal masses. The scales are referable 

 to the Dapedium politum, and other fish that occur in the lias ; the bones 

 are those of fish and also of small Ichthyosauri. The interior of these 

 bezoars is arranged in spiral folds ; their exterior also bears impressions 

 received from the convolutions of the intestines of the living animals. 

 In many of the entire skeletons of young Ichthyosauri, the bezoars are 

 seen within the ribs and near the pelvis: these must probably have been 

 included within the animal's body at the moment of his death. The 

 author found, three years ago, a similar ball of faecal matter, in the collec- 

 tion, of Mr. Mantell, from the strata of Tilgate Forest, which abound in 

 bones of Ichthyosauri and other large reptiles; and he conjectures that 

 these bezoars exist wherever the remains of Plesiosauri are abundant. 



o. Fossil Sepia. An indurated, black, animal substance, like that in the 

 ink-bag of the cuttle-fish, occurs in the lias at Lyme Regis ; and a drawing 

 made with this fossil pigment, three years ago, was pronounced by an 

 eminent artist to have been tinted with sepia. It is nearly of the colour 

 and consistence of jet, and very fragile, with a bright splintery fracture; 

 its powder is brown, like that of the painter's sepia. It occurs in single 

 masses, nearly of the shape and size of a small gall-bladder, broadest at 

 the base and gradually contracted towards the neck; these are always 

 surrounded by a thin nacreous case, brilliant as the most vivid lumachella. 

 The nacre seems to have formed the lining of a fibrous, thin, shelly sub- 

 stance, which, together with this nacreous lining, was prolonged into a 

 hpllow cone, like that of a belemnite, beyond the neck of the ink-bag. 

 Close to the neck of the ink-bag there is a series of circular transverse 

 plates and narrow chambers, resembling the chambered alveolus within the 

 cone of a belemnite ; but beyond the apex of this alveolus, no spathose 

 body has been found. 



The author infers that the animal from which these fossil ink-bags are 

 derived, was some unknown cephalopode, nearly allied in its internal 

 structure to the inhabitant of the belemnite, the circular form of the 

 septa showing that they cannot be referred to the molluscous inhabitant of 

 any nautilus or cornu-ammonis. 



Feb. 6th. —A paper was read " On the Oolitic District of Bath," by 

 William Lonsdale, Esq., of Bath-Easton. 



The tract described in this paper comprehends a space included between 

 the lines passing, on the north, from Wycke, north west of Bath, through 



I 



