•618 REPOBT— 1881. 



The conclusions arrived at from the facts are — • 



1st. That the boulder clays were formed in the sea, partly hy glacial action and 

 partly hy icebergs. The occurrence of boulders from distant localities — often in 

 very different directions — in a matrix partaking of the character of the underlying 

 rocks, is explained in an entirely new way. 



2nd. That the middle sands and gravels are the result of marine and river 

 action combined. 



•3rd. That the mounds of sand and gravel occurring in the mouths of valleys 

 were accumulated by floating ice, from pre-existing deposits. 



A new explanation was given of the occurrence of boulders at higher levels than 

 the rocks from which they were derived. 



7. On Simosaurus pusillm (Fraas), a step in the Evolution of the Plesio. 

 sauria. By Professor H, G. Seeley, F.E.S., F.L.8. 



The author gave a detailed description of the skeleton of Simosaurus, recently 

 discovered in the Trias near Stuttgard, and briefly noticed and figured by Dr. 

 Oscar Fraas. He then drew special attention to the differences from plesiosaurus, 

 especially in the form of the pectoral arch, and in the characters of the fore and 

 hind limbs. 



Hence we see in Simosaurus a land animal in process of adaptation to natatory 

 conditions. The width of the humerus appears to have relation to a lateral flexure 

 of the fore limb, by which the bone became the chief agent in movement on land ; 

 and as the land-progression was not entirely lost, the fore arm had not become 

 reduced in length to the plesiosaurian form. The small number of phalanges was 

 similarly explained. The hiud limb was discussed to show how it might assume 

 like characters with the fore limb. The author concludes that the plesiosauri 

 were originally land animals, and that their ancestors and affinities must be sought 

 in Simosaurus, Nothosaurus, and allied types of amphibious Triassic reptiles. 



8. 071 a restoration of the skeleton of Archceopteryx, with some remarks on 

 the cUferences between the Berlin and London specimens. By Professor 

 H. G. Seeley, F.B.8., F.L.S. 



The author, by tracing the forms of the bones from a photograph, arranged the 

 skeleton so as to represent a bird which stood about ten inches high. The head 

 has a post-occipital process similar to that which occurs at a separate bone in the 

 cormorant ; the neck is curved forward ; the tail reached almost to the ground, 

 and the limbs were carried exactly as in birds. 



The Berlin fossil certainly belongs to a distinct species ; almost as certainly to 

 a distinct genus, and is probably the type of a distinct family of saururous birds. 

 The author did not name the fossil, believing that duty to devolve upon the writer 

 who may hereafter figure and describe this fossil. 



SA TUB DAT, SEPTEMBER 3. 



The following Papers were read : — 



1. On Asterosmilia Beedi, a new species of coral from the Oligocene of 

 BrocJcenhurst, Habits. By Professor P. Martin Duncan, F.B.S. 



The museum of the Philosophical Society of York contains, thanks to the industry 

 and generosity of Mr. E.eed, a very interesting series of corals from Brockenhurst 



