Correspondence — Bev. T. G. Bonney. 239 



The Shap Fell boulders occurring in YorbsHre are found in the 

 Purple Clay of Mr. S. V. Wood, jun,, and in the upper Boulder- 

 clay of Mr. Mackintosh, both of which deposits I consider to be 

 synchronous with the upper Boulder-clay of Lancashire, in which I 

 have found a few pebbles of this granite as far south as the Mersey. 

 The blocks I believe to have been detached during the middle sand 

 period by the action of breakers, which formed them into a beach 

 on the slope of the Fell, which on the climate becoming colder 

 were floated off by coast-ice, and carried by the flow tide eastwards 

 to Yorkshire and southwards to Lancashire. I cannot therefore 

 agree with Mr. Croll, admirable as are his investigations as regards 

 Scotland, that the total ice-wrap theory is applicable to north- 

 western England, and more especially to the transport of Shap Fell 

 boulders. Chakles E. de Kance, F.G.S. 



TEREACES OF NORWAY. 

 Sir, — As I have had the opportunity of examining several of the 

 terraces of Norway described by Professor Kjerulf (as noticed in the 

 Geological Magazine, p. 74), and agree with his explanation of 

 them, I may, perhaps, be excused for replying to Colonel Green- 

 wood's letter (p. 191). I have never felt satisfied with his explana- 

 tion of the Fraser Eiver and Himalaya terraces, and I feel convinced 

 that it will not apply to those of Norway. The latter are, I believe, 

 formed as follows : — First a delta has been deposited, when some 

 physical cause has diminished the velocity of a stream which sweeps 

 along detritus; e.g. where a river enters a fjord. This delta has, 

 after a time, been raised above the water, and during the period of 

 upheaval and the subsequent pause the stream has cut away a con- 

 siderable portion of the loose materials of the delta. A further up- 

 heaval, with an increase in the velocity or reduction in the volume 

 of the stream, has carved another and lower set of terraces during 

 another pause, and so on. Of course, if local conditions permit, new 

 deltas may form further down the valley in the part which yet 

 remains under water ; and these in turn may be subjected to erosion, 

 if the upward movement is resumed. My reasons for differing from 

 Colonel Greenwood are — putting them as briefly as possible — (1) 

 Eegular cliffs and grooves, to say nothing of deposits of marine 

 shells, at various heights above the present sea-level, show that 

 Norway has risen during recent epochs, and that there have been 

 pauses in the upheaval. (2) Many valleys (as at the head of the 

 Alten fjord) in the neighbourhood of these signs of upheaval are 

 filled with wide plains of drift, out of which the river has cut a 

 channel, and the fjord face of this plain is regularly terraced. 



(3) That, as in some of the valleys of the Sogne Fjord (and doubt- 

 less in many others), the terraces show similar faces looking both to 

 the fjord and to the river, suggesting the same cause for their forma- 

 tion, viz., the erosion of incoherent materials by water in motion. 



(4) That in ascending a valley you not unfrequently find sets of 

 terraces rising step above step, not from the stream, but up the 

 stream ; so that in the upper part of the valley the corresponding 



