306 ADAMSON : THE YORKSHIRE BOULDER COMMITTEE. 



Vegetation dwarfish and scanty ; very few trees exist ; the winds 

 are too strong and the climatic conditions generally are too severe 

 for tree growth ; besides, the soil is scanty and wet. 



Boulder Clay is absent above the 850 ft. Ordnance datum. 

 Gravel is also absent, and no sand worth the name is met with. 

 Pebbles are few. Valley alluvium coarse and scanty. 



The Yoredale shales crop out at Rag Stones and Reddycon 

 Dean ; at the latter place the shales are very carbonaceous and much 

 faulted. 



Area examined between the 850 ft. and 1,268 ft. Ordnance datum. 



The Castleshaw Valley. 



GROUPS OF BOULDERS. 



Few boulders have as yet turned up. Those which have been 

 gathered are small Syenites about 1 2 in. square, and Silurian Grits ; 

 the Syenites are round, but the Silurian Grits are angular, one 

 specimen (1 ft. 8 in. x 1 ft. 3 in. x 8 in.) having very sharp anglers; 

 small Eskdale Granites turn up occasionally, much worn as usu al. 

 One specimen of Silurian Grit in my possession is nicely striated 

 and smoothed. 



Isolated Boulder. 



Near Water's Mill an Erratic lies in the middle of a small field. 

 4 ft. 6 in. x 2 ft. 6 in. ; hornblendic trap; elongated and sub-angular; 

 longer axis trends S.W. ; upper face only exposed. 



Notes. — This valley is carved in the Yoredale Shales. The 

 surrounding hills are capped with Kinderscout Grit. Grey Shales, 

 fully 250 ft. thick, lie between the Kinderscout and the hard and 

 somewhat massive 'Bakestone' shale which is unchanged in 

 character for more than 50 ft. without coming to its base. The hills 

 at the top of the valley rise to 1,300 ft. above the sea. The hills at 

 the bottom end of the valley are mamillated. The slopes are 

 gentle. 



This valley is recent, and conclusive evidence of a former lake 

 exists, which had a large area. Boulder Clay none ; local clay and 

 loam, an ample supply ; coarse gravel in the centre of the valley, at 

 one place 14 ft. thick. Sand about 3 ft. thick, both fresh-water and 

 partially lacustrine. A few pebbles. 



Area examined between 700 ft. and 1,200 ft. Ordnance datum. 



The following were exhibited before the Geological Section of 

 the Yorkshire Naturalists' Union, on their examination of the Castle- 

 shaw Valley : — 



Naturalist, 



