GLACIOLOGY OF THE SOUTH ORKNEYS. 845 



is rapid, and near this line the ice bands in the neve are gradually getting thicker and 

 closer set. The depth of this top layer is about 8 feet. On some smaller glaciers, such 

 as that shown in Plate VIII. fig. 1, the separation between the nev6 and the ice is very 

 sharp. This is due to the fact that the stratification of the latter is not quite hori- 

 zontal, the layers being rather higher at the sides than in the centre. On larger sheets 

 the separation is marked mainly by the overhang of the surface layers. 



Stratification. — Below these granular neve-ice layers we come to the main part of 

 the cliff, formed of strata of ice varying in thickness from about 6 inches to 1 foot, or 

 occasionally as much as l|- feet. There is no sign of any projection of any of these 

 layers such as might be caused by one stratum sliding bodily over its fellow below. 

 The layers are not definitely formed of alternating blue and white bands, all being much 

 alike in density and colour. They are light blue and contain numerous air-bubbles. 

 On cutting into the ice a little way, however, so that a surface is obtained which has 

 not been exposed to the sunlight, the ice is found to be much more solid than appears 

 on an exposed face. The appearance usually observed is undoubtedly partly due to 

 disintegration (see further notes on ice-grains, p. 847). Near the sole of the glacier 

 the ice becomes extremely solid, but never attains the intensely deep-blue colour so 

 characteristic of some of the large tabular bergs. Above the level of the snow talus 

 there is not much englacial debris to be seen — a very occasional boulder, but principally 

 only fine earthy material and small angular fragments under half an inch in diameter. 

 Some of this material is actually in the ice layers, but most of it occurs as a dirt band 

 between them. On melting, this material gets washed down fairly evenly over the face, 

 giving one an exaggerated impression of the amount of dt^bris and a false idea of its 

 position, but the real state of affairs can at once be seen on a newly fractured face. 

 These are layers of " fossil cryoconite," as Nordenskjold calls them, and show that each 

 of the strata corresponds to a season's snowfall. Similar material was seen on the 

 surface of the Scotia Bay ice-sheet in summer — small rocky wind-blown fragments and 

 earthy matter derived from the surrounding hills. These led to the formation of the 

 usual shallow dust-wells around each particle. 



Although outcropping horizontally on most terminal faces, in the section of the 

 glacier exposed on the east side of Uruguay Cove where the section is semi-longitudinal 

 to the direction of flow (see plan on p. 850, text-fig. 10), the stratification is seen to be not 



Text-fig. 7. — Upward inclination of strata towards glacier snout terminatioB. 



quite horizontal but rising slightly towards the termination. There is no sudden upturn- 

 ing of the layers at the end, as described by Chamberlin in some of the North Greenland 

 glaciers, but the section shows how even in such a small ice-sheet as this there may be 

 some uplift of bottom material. That it actually does occur to some extent is shown, 

 I think, by the fact that in the small moraine at the end of the snout in which this 



