Rev. T. G. Bonney — Notes on Glaciers. 197 



referred to; and also the defensive spines of a fish, Aster acanthus, 



Shells of Ammonites, numerous small Oysters, and other Mollusca 



abound in the clay, but they are all compressed and too friable for 



removal. 



EXPLANATION OF PLATES. 



PLATE YIL 



EiG. 1. Eougli diagram of principal mass of septarium in wliicli the greater part of 

 tlie remains of Omosaurus armatus, Owen, were enclosed. 

 /. the right femur in situ. pu. the right pubic bone projecting from the 

 nodule into the surrounding clay-bed. is. the left ischium. Six caudal 

 vertebrae {c) are also seen lying near the septarium in the clay. 

 „ 2. General view of the pit at Swindon, showing the relative position of the 

 large septarium {a) and the five adjacent septaria b, b, b (from a rough 

 sketch by the author). 



PLATE VIIL 



Fig. 1. Omosaurus armatus, Owen, as it appeared after development from the sep- 

 tarium. 

 sa. the sacrum, il. the iliac bones, a. the acetabulum into which the 

 femur (/) was articulated, is. the ischium, nearly in situ. d. the dorsal 

 vertebrae, c. the caudal vertebrae. 

 ,, 2. The left humerus. 

 .,, 3. The right pubic bone. 



II. — Some Notes on Glaciers. 

 By the Eev. T. O. Bonney, M.A., F.G.S. 



AS missiles are falling thick like hail upon Mr. Judd since his 

 challenge to the Glacialists, I take the opportunity of putting 

 together a few notes, made during an Alpine journey last summer, 

 which would have been published sooner, had more time been at my 

 disposal. The lower parts of the Gorner, Arolla, Des Bossons, Des 

 Bois, and Argentiere Glaciers were carefully studied, but others 

 received passing attention. 



1. Ground Moraine. — The Glaciers of the Swiss and Savoy 

 Alps have been retreating for several years ; hence if anything like 

 ground moraine existed, this would be a very favourable time for 

 observing it. In no case have I been able to find signs of any 

 deposit resembling Till or Boulder-clay ; the detrital matter which 

 is scattered, generally sparsely, over the slope left bare by the retreat- 

 ing glacier, has fallen from its surface, like ordinary terminal moraine. 

 Further, by availing myself of crevasses, etc., I have made niy way 

 occasionally for some little distance beneath the ice. Nothing has 

 been seen but bare rock, with now and then a film of mud or a 

 passing stone. In short, the result of an experience of some years 

 has convinced me, that if anything like the Till or Ground Moraine of 

 recent glacialists exists in the Alps, it is a very local and exceptional 

 phenomenon. It had sometimes occurred to me, as I believe it has 

 to others, that much till-like matter might be produced from a resi- 

 duum of stones and mud which had been once involved in the ice of 

 the glacier. My more careful observations during the present year 

 have shown me that these cases of included materials are more 

 exceptional and less abundant than I had anticipated. 



.2. The Erosive Power of Glaciers. — As I have already several 



