66 i). iV. 'Peach and J. Some — The Glac'iatlon 



tion of the striated surfaces, and specially of the dispersal of the stones 

 in the Boulder-clay, that, during the primary glaciation, the Scandi- 

 navian ice-sheet abutted on the eastern seaboard of Shetland with a 

 W.S.W, and S.W. trend, and after reaching the crest of the Main- 

 land, it swung round to the N.W. and N.N.W. 



With reference to this statement, Mr. Milne Home makes the 

 following remark : " Even on the east coast of the Shetlands, where 

 the striations should show a N.E. direction, there is no uniformity in 

 that direction. Near the south end of the group, viz. at Bressay 

 and Ticrwick, as the arrows on the map show, the direction of the 

 striaa is not from N.E. to S.W., but from N.W. to S.E." 



No reference is made in the foregoing sentence to the fact that the 

 south-easterly strite at Lerwick and at certain localities in Bressay 

 belong to the period of local glaciation. Neither is any allusion 

 made to the existence of cross-hatches along the shore at Lerwick ; 

 the older markings running S.W., and the newer ones S. 40° E. 

 Moreover, we distinctly pointed out in our paper, that the south- 

 westerly movement of the ice-sheet during the primary glaciation in 

 the Lerwick and Quarff districts is placed beyond doubt, by the occur- 

 rence of striated blocks of Old Eed Sandstone grits and flags in the 

 Boulder-clay on the west side of the island near Quarflf. On the 

 other hand, we indicated that the presence of striated fragments of 

 schists and slates from the Cliff Hills, in morainic deposits in the 

 neighbourhood of Lerwick, points to a local radiation of the ice 

 which was only powerful enough to invade the north-western jpart of 

 the island of Bressay. 



Eegarding the direction of the ice-flow in Unst, Mr. Milne Home 

 says : "Also at the north end of the group of islands, viz. in Unst, 

 though the authors of the paper represent by contour lines, and also 

 by the text, the direction of the movement to have been from N.E. 

 to S.W., considerable doubt must be felt on that point because of 

 the contrary testimony of Mr. C. W. Peach, as given in the British 

 Association Keports for 1864. Mr. Peach states ' that ruts and 

 strife fell under his notice in North Unst, on the cliff at Hagdale in 

 Haroldsnick Bay ; the direction being nearly W.N.W. and E.S.E.' 

 Mr. Peach says ' that in ascending the Muckle Heog Hill, which 

 reaches a height of at least 500 feet, he found the W.N.W. end 

 vertical and polished, to the depth of 150 feet,' " 



The discrepancy between the observations of Mr. C. W. Peach 

 and ourselves may be best explained by quoting from a letter dated 

 November, 1880, which he has kindly forwarded to us, and 

 which, he has permitted us to use in our reply to this address. " I 

 send you a copy of my paper on Shetland, read before the lioyal 

 Physical Society, Edinburgh, in which I stated that the strias on the 

 Muckle Heog, Unst, ran nearly W.N.W. and E.S.E. In the closing 

 sentence of that paper I also stated that all the bearings are by 

 compass, no allowance having been made for variation. This 

 should be taken into consideration and the deviation allowed for as 

 far as Shetland is concerned. Since I wrote that paper, having seen 

 much more of the glaciation of Scotland and thought more about it, 



