166 



Proceedings of the Royal Physical Society. 



Direction. 



E. iS. 



(magnetic. ) 



E.— E.N.E. 



(magnetic. ) 



E. 30 N. 

 (magnetic. ) 



E. 10 N. 



E.N.E. 



Nearly E. and W. 



E. and W. 



E. 10-15 N. 



(5 boulders.) 



E. 5 N.— E. 15 N. 



(42 boulders. ) 



E. 10 K 

 (4 boulders.) 



E.— E. 30 S. 

 (7 boulders.) 



Observer. 



Milne Home, Trans. Roy. 

 Soc, Edinb., vol. xiv., 

 p. 311 (1838). 



Milne Home, Trans. 

 Geol. Soc, Edinb., vol. 

 ii., p. 346. 



Hugh Miller, Edinburgb 

 and its Neighbourhood, 

 p. 35. 



John Henderson, Trans. 



Edinb. Geol. Soc, vol. 



ii., p. 392. 

 Henderson, ihid., vol. ii., 



p. 200. 



Locality. 

 Newhaven and Edinburgh ) 

 railway, . . .\ 



On the shore at Joppa, . 



Sand pit, Tynecastle, 



Fillyside, west of Porto- 



bello, .... 

 Near Magdalen Bridge, 



east of Portobello, 



New Redhall Quarry, 



Whelpside, Water of Leith, jl 

 above Currie, . , i| 



Rothesay Place, Edin- 

 burgh, 



Granton pier, west of 



Custom House, . . , ^ 



Cutting, Suburban Rail- j -r, i n isr J" ■^- Milder, 



way, between Joppa and 

 Niddrie, 



Cutting, Suburban Rail- 

 way, Colin ton Road, . 



The unanimity of this evidence is obvious at a glance. It 

 is especially interesting to observe the tendency in both 

 kinds of strise to divide around Arthur's Seat. 



Little more need be said about the evidence of direction 

 furnished by the glaciation of boulders lying in sitn in the 

 till.^ There are some further details, however, which the 

 glacialist will pardon me for entering upon. Some of these 

 may be found of practical use in reading off the evidence in 

 the field ; some of the others have more or less of a general 

 bearing. 



Adjustment of the Boulders under Glaciation. 



The adjustment of boulders under glaciation generally 

 resembles that of small roches moutonnSes. The side facing 

 the ice is apt to be tilted slightly towards it, or to be ground 

 down into a smooth slope with flowing outlines. The averted 

 or sheltered side, again, retains more or less of its roughness. 



1 I must not omit to state that, on comparing notes on the subject with 

 my friend and colleague, Mr B. N. Peach, I learned that he has for many 

 years been in the habit of observing this evidence of direction and noting it 

 upon his maps. The extent of Mr Peach's acquaintance with the geology of 

 Scotland renders his testimony extremely valuable. 



