Geological Society. 233 



formerly occupied by a lake, or that the surface of the vale was once 

 nearly on a level with the entrance of the cave : and he explains the 

 position of the loam and associated pebbles and bones by supposing 

 that a sudden flood, rushing through the valley, carried into the cave 

 the pebbles, fragments of wood, and loam found in its lower part :: — 

 that after this inundation no similar catastrophe occurred for an un- 

 known period, during which the caves again became the resort of 

 wild animals : — that at the close of that period another and more pow- 

 erful flood occurred, rising above the level of the caves, and deposit- 

 ing within it, the loam which occupied the greater part of its cavity ; 

 and that this flood, overcoming every obstacle, excavated the valley to 

 its present depth. 



The memoir was illustrated by numerous drawings of the caves and 

 bones, a ground plan, and a manuscript map of the district. 



June 13. — A paper was first read, entitled "Observations on the 

 London Clay of the Highgate Archway," by Nathaniel Wetherell, 

 Esq., F.G.S. 



This communication, which was accompanied by a series of speci- 

 mens, gives a full account of the position, extent, and order of the 

 beds cut through in making the excavation for the archway, and a 

 list of the fossils found in the lowermost stratum or the London clay. 



For the details respecting the order of the beds the author refers 

 to the "Outlines" of the Rev. William Conybeare and the late Mr. 

 Phillips; and after enumerating the fossils found in the clay, points 

 out that the species of most common occurrence were Peclunculus 

 decussatus, Natica glaucinoides, Modiola clegans, and Teredo anienauta, 

 and that those of rarest occurrence were Acteon elongatus, Cypraa 

 oviformis, Neritina concava, and Serpula crassa. 



A paper was afterwards read giving " An account of the Discovery 

 of portions of three Skeletons of the Megatherium in the province of 

 Buenos Ayres in South America," by Woodbine Parish, jun. Esq., 

 His Majesty's Charge d'Affaires and Consul General at Buenos Ayres j 

 followed bv a description of the bones by William Clift, Esq. F.G.S. 

 F.R S. 8cc. &c. 



Mr. Parish some years since presented to the Geological Society 

 several large bones of mammalia, discovered in the valley of Tarija 

 on the confines of Bolivia, and being anxious to procure further 

 specimens, he institi'ted a series of inquiries, by which he ascer- 

 tained that the teeth and bones of quadrupeds had been frequently 

 met with in the province of Buenos Ayres, especially in the neighbour- 

 hood of the river Saiado, and in the beds of its tributary lakes and 

 streams ; as well as in the adjoining province of Entre Rios, and that 

 in the Banda Oriental a nearly perfect skeleton was once found. 



During these inquiries Mr. Parish was informed that some bones 

 of extraordinary size had been found in the bed of the Rio Saiado, and 

 brought to Buenos Ayres from the Estancia of Don Hilario Sosa. On 

 inspecting them he was immediately struck with their resemblance to 

 the remains of the Megatherium formerly sent to the Museum at 

 Madrid by the Marquis of Loreto, and likewise procured in the |)ro- 

 vince of I3ucnos Ayres. These bones, the property of Don Hilario 



Third Series. Vol.1. No. 3. Sept. \832. 2H 



