74 REPORT — 1856. 



Darwin, Esq., F.R.S., at Punta Alta, Northern Patagonia, These portions were 

 described by the author in the appendix to the ' Natural History of the Voyage of 

 H.M.S. Beagle.' The subsequent acquisition by the British Museum of the collec- 

 tion of Fossil Mammalia brought from Buenos Ayres by M. Bravard, has given further 

 evidenceof the generic distinction ofScelidotherhtm, aud has supplied important charac- 

 ters of the osseous system, and especially of the skull, which the fragments from the 

 hard consolidated gravel of Punta Alta did not afford. The best portion of the cra- 

 nium from that locality wanted the facial part anterior to the orbit, and the greater 

 part of the upper walls ; sufficient, however, remained to indicate the peculiar charac- 

 ter of its slender proportions, and hence Professor Owen has been led to select the 

 name leptocephalum for the species, which is undoubtedly new. The aptness of the 

 epithet ' slender headed,' is proved by the author's researches to be greater than could 

 have been surmised from the original fossil ; for the entire skull, now in the British 

 Museum, exhibits a remarkable prolongation of the upper and lower jaws, and a 

 slenderness of the parts pi-oduced anterior to the dental series, unique in the leaf-eat- 

 ing section of the order Bruia, and offering a very interesting approximation to the 

 peculiar proportions of the skull in the Ant-eaters. The original fossils from Pata- 

 gonia indicated that they belonged to an individual of immature age : the difference of 

 size between them and the corresponding parts in the British Museum, depends on 

 the latter having belonged to full-grown individuals : the slight difference in the shape 

 of the anterior molars seems in like manner to be due to such an amount of change 

 as might take place in the progress of growth of a tooth with a constantly renewable 

 pulp. Professor Owen finds at least no good gi-ounds for inferring a specific distinc- 

 tion between the fossils of the old animal from Buenos Ayres, and the younger 

 specimen from Patagonia. The author then proceeds to give a detailed anatomical 

 account of the fossil bones in the British Museum, instituting a comparison betweeu 

 them and the bones of other large extinct animals, especially those of the Edentate 

 order. The Scelidothere was a quadruped of from eight to ten feet in length, but not 

 more than four feet high, and nearly as broad at the haunches, the thigh-bones being 

 extraordinarily broad in proportion to their length. The trunk gradually tapered 

 forwards to the long and slender head. The fore-limbs had complete clavicles, and 

 the rotatory movements of the fore-arm. All the limbs were provided with long and 

 strong claws. The animal had a long and muscular tongue, and it is probable that 

 its food might have been of a more mixed nature than that of the Megatherium. 

 But it was more essentially related to the Sloths than to the Ant-eaters. In conclusion, 

 the author remarks, that as our knowledge of the great Megatherioid animals increases, 

 the definition of their distinctive characters demands more extended comparison of 

 particulars. Hence in each successive attempt at a restoration of these truly remark- 

 able extinct South American quadrupeds, there results a discription of details which 

 might seem prolix and uncalled for, but which are necessary for the proper develop- 

 ment of the task of reproducing a specimen of an extinct species. 



These details of the osteology and dentition of the Scelidotherium leptocephalum, it 

 is the intention of the author to communicate, with the requisite illustrations, to the 

 Royal Society of London. 



On the Beekites found in the Red Conglomerates of Torbay. 

 By W. Pengellt, F.G.S. 



Perhaps the most interesting things found in the red Triassic conglomerates of 

 Torbay are the Beekites, so named from the late Dr. Beeke, Dean of Bristol, by 

 whom, it is believed, they were first noticed. They vary in size from half an inch 

 to a foot, but the more common dimensions are from three to six inches in mean 

 diameter. Their surfaces are covered with chalcedony, generally arranged in tuber- 

 cles, each of which is not unfrequently surrounded by one or more rings, and occa- 

 sionally the same ring invests two or more tubercles, or sets of rings. 



The interior of the Beekite is calcareous. In most instances the nucleus is under- 

 going decomposition and is only partially attached to the shell ; sometimes it is entirely 

 detached, and rolls about within the cavity when shaken ; not unfreijuently it is 

 reduced to a dark-brown or iron-grey powder, which effervesces in acids. 



The nucleus appears to be always a fossil, aud is either a sponge, a coral, a shell. 



