SECTIONAL TRANSACTIONS.— C. 549 



ft. in. 



(1) Soil 10 



(2) Sand 10 



(3) Browni.sh sandy boulder clay: the lower 18 in. hard and 



concretionary and with an irony cement . . .10 

 {4) Stiff bluish or greenish clay, with faint reddish tinge ; almost 

 stoneless, but with fragments uf the underlying peat. 

 (There were signs of disturbance at the junction of (4) 

 and (.5)) 



(5) Peat or lignite, with abundant remains of beetles 



(6) Greenish stoneless silt ....... 



(7) Compact boulder clay with many scratched boulders . 



(8) Gap ......... about 



(9) Carboniferous shales. 



The peat or lignite (bed No. 5) is a hard, compact, laminated material, deep broMu 

 in colour and sometimes showing slicken-sided joint surfaces. It compares closely 

 in appearance with some of the lignites of Germany. It is made up of flattened grass- 

 like leaves and stems — no rounded woody stems were noted — and contains a profusion 

 of beetle remains. The deposit does not occur as a regular bed, but as a layer of 

 cakes of laminated lignite enveloped in clay and inclined in various directions usually 

 at low angles. It is clear that it is not lying in the position in which it was formed ; 

 originally continuous it has been moved and broken up by the pressure of the over- 

 riding boulder clay (bed No. 3). It indicates the existence at this locality of a marsh 

 or loch, the deposits of which were disturbed during the readvance of the ice sheet 

 and incorporated in part in the lower portion of the boulder clay. Similar peat beds 

 have been noted elsewhere in Scotland, as for example, at Faskine, near Airdrie 

 {vide Trans. Geol. Soc. Glasgow, vol. x, part 1, 1895, p. 148), and at Cowdenglen in 

 Renfrewshire (op. cit., vol. ix, part 1, 1891, p. 213). 



The plants of which the lignite is composed have not yet been determined. The 

 beetle remains in the lignite, which are abundant, have been submitted to K. G. 

 Blair, of the British Museum, who has I'eported on them as follows : — 



' Most of the species, or their very close allies, have previously been found in peat 

 deposits though it is rather striking that Donacia, the genus usually most in evidence 

 in peat deposits, is entirely lacking from the material now submitted. 



' The three species most plentifully represented are Patrobus septentrionie, 

 OlopTirum fuscum and Nolaris cethiops ' — all northern forms. 



Dr. G. Slater. — Studies on the Rhone Glacier, 1927. 



The investigation of the Rhone Glacier by the author in 1927 was confined to two 

 lines of inquiry : (1) The structure of the ice forming the concave side of the south- 

 eastern flank of the glacier ; (2) The relationship between the air-temperature and 

 rate of the surface melting of the ice. 



1. The surface of the marginal ice was marked into 50-foot squares, and the 

 structure plotted on a map to a scale of 50 feet to an inch. The ice formed a mound 

 dissected into ridges by three longitudinal, basin-shaped trenches, wliich were heavily 

 crevassed laterally and bounded by crevasse-like walls of ice longitudinally. Thrust- 

 planes dipping at high angles formed a characteristic feature of the ridges. In plan 

 they formed radiating groups, the fulcrum of each group being near the margin of 

 the lateral moraine. The trend of these thrust-planes varied progressively south- 

 wards, from N.W.-S.E. to E.-W. approximately, and adjacent pairs formed the jaws 

 of squeezed wedges of ice showing displaced ribbon-structure. Crevasses radiated 

 from the lateral moraine and in places dissected the junctions of the thrust-planes. 

 The structure as a whole suggests pivotal movement of the compressed marginal ice, 

 the ' trenches ' representing tensional areas due to the deviation in direction south- 

 wards of the movement of the ice, from the normal south-westerly trend. Relief 

 from pressure was obtained both laterallj' and longitudinally by the squeezing inwards 

 of the ice towards the tensional areas on the one hand, and by the upward rising of 

 the ice along thrust-planes on the other. 



2. Observations in Spitsbergen, 1921 suggested to the author the following tentative 

 relationship between the average air-temperature and the rate of melting of the ice : — 



t=-32°F. 

 M= 7i 



