Io8 DR. J. A. SMYTHE ON 



gradual clearing of local ice from the hills fringing the 

 granitic central mass. Temporary tarns were thus held up 

 in the land laid bare between the ice-edges, and these in over- 

 flowing notched the many spurs which radiate from the massif. 

 A great series of swires was thus generated ; most of these 

 have been described by Kendall and Muff [15], and reference 

 for details may be made to their paper. In the map the most 

 important of these are marked C 2 to C 17. For reference, the 

 approximate heights of their intakes may be given ; these are, 

 in order of numbering, 700, 625, 1,000, 1,025, 900, 900, 800, 

 1,000, 960, 900, 800, 725, 700, 600, 500, and 400 feet. 

 (Photograph 4). 



The line of cleavage between the Breamish ice and the 

 western sheet followed the lofty ridge running from East Hill 

 to High Knowes. The Breamish ice has marked its retreat 

 by notching four water-partings, Di, D 2, D 3, and D 4 at 

 900, 900, 950, and 1,000 feet respectively. Of these, D 2, 

 Middle Dene, is very deeply cut, and the erratic of Cheviot 

 granite near its intake bears witness to the source of the ice 

 which produced it. 



In no place are the phenomena accompanying the retreat 

 of foreign ice better shown than on the south side of the above 

 ridge, in the neighbourhood of the Spartley Burn and the 

 head of the Aln. The edge of the western sheet there lay 

 parallel to the ridges and across the Spartley and Biddlestone 

 Burns, the result being the production of a great number of 

 marginal trenches along the ridge sides and direct cuts across 

 the water-partings. The first cut Ei (1,020 feet) occurring on 

 Northfield Hill is small, with a double intake, and is the only 

 one of the series which drains westward. An important one 

 follows next in Fawdon Dene, E 2 (700 feet), a huge cleugh 

 draining towards the Breamish and connected with several 

 marginal trenches west of its intake (Photograph 5.). A slight 

 recession now produced the marginal channel E 3 (660 feet). 

 The upper part of the Spartley valley was now free from ice, and, 

 being dammed lower down, overflowed by Coppath, cutting the 

 swires E4 and E 5 (920 and 900 feet), and at Castle Hill E 6 



