Vol. 65.] THE HOWGILL PELLS AND THEIR TOPOGRAPHY. 595 



section. The margins of the drift at the valley-sides are usually 

 well defined. 



The deltoid drift-masses seem to occur when the ice has moved up- 

 valley or transversely thereto, or has flowed over a col into another 

 valley, thus suggesting that they are due to the melting of 

 inert ice. 



Going southwards, we now arrive at the important valley of 

 Carling Gill, the waters of which rise on Fell Head. For more 

 than a mile up from its junction with the Lune, the Carling Gill 

 Valley is wide and U-shaped with truncated spurs, and shows the 

 glacial scooping of which we speak as ' conchoidal ' on the concave 

 sides of its bends. 1 One of the best of these scoops is seen on the- 

 southern bank of the stream west of Green Knott Gill. 



There is much drift on the valley-floor. A deltoid mass of drift 

 cut through by Grains Gill and the lower part of Weasel Gill 

 contains Carboniferous boulders and is traceable up to, and beyond 

 the col which marks the beheading of Ellergill, into the valley of 

 the latter stream. It is clear that the ice which, as before stated, 

 filled Ellergill from the north also gave rise to this delta, which 

 must have been left by a tongue of northern ice coming through 

 the col. 



The top of the U-shaped part of Carling Gill is at a point south 

 of Uldale Head. Here Carling Gill once had three heads. That 

 on the north from Uldale Head (Great Knott Gill) is now marked 

 by a U-shaped valley, with a combe at the head and a deltoid mass 

 of drift below. Small Gill on the south side is also a well glaciated 

 U-shaped valley with much drift, and ice may have traversed the pass 

 at its head to Fair Mile Beck on the south. Traces of a third head 

 are also seen in the slightly modified slopes west of Black Force \ 

 but the shape of the ground shows that there ice-erosion has had 

 but little effect. It is into this central head that the streams which 

 have been diverted into Carling Gill flow. 



Dr. Strahan detected the diversion of the old Uldale waters 

 into Carling Gill, but does not notice the deflection of those of the 

 Little Ulgill Beck Valley which forms Black Force. In the Geo- 

 logical Survey Memoir (' The Geology of the Country around Kendal, 

 Sedbergh, &c.' 1888, pp. 45-46) he writes 



' In the head of Uldale a remarkable instance of the intersection and tapping 

 of the water of one dale through the eating back of the head of another has 

 been observed. It will be seen by the distribution of the Drift that the Uldale 

 Valley starts under Wind Scarth and crosses the County Boundary. The hills 

 forming the west side of the valley, however, are breached at the County 

 Boundary by a deep and rocky but narrow ravine, by which the water collected 

 under Wind Searth finds its way direct to the Lune at Carlingill, instead of 

 following the Uldale Valley to Graisgill. There can be little doubt that origi- 

 nally Uldale formed a continuous line of drainage up to the foot of Wind 



1 This term is used, because the ice gives rise to concave scoops recalling the 

 appearance of the inner side of the valve of a clam-shell. 



