96 T. M. READE ON THE DRIFT-BEDS OE THE 



striation or planing on any of the numerous erratics I examined. 

 There is at Styperson, covering the rock, a red clay with erratic 

 stones ; but all over these hills, as far as Whaleybridge, drift is 

 generally absent. 



Drift of the liivington Hills. 



Perhaps the most interesting section of the Drift occurring 

 among the hills was that shown by the excavation for the puddle- 

 Pig. 12. — Turner's Trench, Yarrow Reservoir, 1872-75. 



(Horizontal and vertical scales 220 feet to 1 inch.) 

 w. E. 



A, A. Bottom, as exoavated. G. Gravel. 



B, B. Shale excavated. H. Good blue clay, containing a few 



C. Gravel and sand. • stones, sand-veins, and some gravel. 



D, D. Loam. I. Peat and clay. 



E. Boulders and gravel. J. Soil. 



F. Gravel and sand. 



wall of the Yarrow Eeservoir at Eivington*. The site of the 

 reservoir is to a large extent in the coal-shales, as proved hy the 

 tunnels and trenches. The river Yarrow runs from Allan's Bridge 

 into the Anglezark Eeservoir ; and the valley dammed up by the 

 embankments thrown across at two points to form the Yarrow 

 Eeservoir is a side valley, which the excavations proved was the 

 Preglacial valley of the Yarrow. This had been sufficiently filled 

 up with drift-deposits to divert the river up to the valley of the 

 Anglezark Eeservoir. The excavations for what was called Turner's 

 Trench (fig. 12) disclosed a gully in the solid rock 140 feet deep from 

 the surface, which, from the winding of its course, was intersected by 

 the same trench in two places, G and H. The bottom was in Mill- 

 stone Grit, which had a surface highly waterworn. The lower part 

 of the gully, Mr. Martin, the resident engineer, informed me, was 

 tilled up with gravel, sand, and large stones, the largest being 

 boulders of Millstone Grit. The upper part was of blue Boulder- 

 clay ; and throughout there were waterworn boulders and pebbles of 

 limestone, granite, porphyry, and greenstone. The excavation for 

 the puddle-wall of the Yarrow embankment intersected the same 

 gully at a higher level, and was filled up with loam, sand, veins 

 of gravel, and boulders (fig. 13). 



* The Yarrow is a tributary of the river Douglas between the Mersey and 

 the BAbble. Not having devoted a special division to the basin of the Douglas, 

 the description of the Drift is most naturally in place here. 



