^Q2 B. N. PEACH AND J. HOENE ON THE 



Moreover, on referring to the chart showing the probable path of the 

 ice in the North Sea, which accompanies this paper (PL XXVII.), it 

 will be seen that it is impossible to escape this conclusion. The ice, 

 which radiated from the north-east of Scotland, not only filled the 

 basin of the Moray Firth, but likewise spread over the low grounds of 

 Banffshire and Aberdeenshire. The researches of previous investi- 

 gators point to this conclusion ; and quite recently, during the pro- 

 secution of the Geological Survey of the south side of the Moray 

 Firth, additional facts have transpired which tend to confirm it. 

 Further, in the neighbourhood of Dunbeath, on the Caithness coast, 

 the strisD gradually swing round till they run parallel with the 

 shore, eventually bending inland till they point towards the north- 

 west, in harmony with the trend of the ice-markings in Orkney. 

 Clearly, then, the ice must have been deflected so as to override the 

 low grounds of Caithness, as pointed out long ago by Dr. CroU. 

 Similarly in Forfarshire and Kincardineshire, the ice which moved 

 off the south-east slopes of the Grampians, on reaching the coast- 

 line, was bent round in a N.N.E. direction, as indicated on the 

 chart. A glance at the chart will also show how the land-ice was 

 deflected along the south-east coast of Scotland, as described by our 

 colleague Dr. James Geikie, F.E.S. ISTow these marked deflections 

 undoubtedly point to some opposing force which was capable of 

 overcoming the seaward motion of the Scotch ice-sheet. Had it 

 been allowed to follow its natural pathway then the phenomena 

 would have been widely different. 



The results of our investigations in Shetland prove that the Scan- 

 dinavian mer cle glace not only invaded the North Sea, but likewise 

 overlapped that group of islands in its march to the Atlantic. The 

 presence of this mass in the bed of the German Ocean furnishes a 

 satisfactory explanation of the phenomena above referred to ; for the 

 two ice- sheets must have coalesced on the sea-floor, and the com-, 

 bined ice-field would naturally take the path of least resistance. 

 In other words, one portion would flow north-westwards by the 

 Orkney Islands, while the southern portion would flow in the direc- 

 tion of the English coast, as laid down on the chart. In all pro- 

 bability the dividing line would be somewhere opposite the basin of 

 the Forth. 



We can quite well understand therefore how the Scotch ice-sheet, 

 as it crept outwards along the bed of the Moray Firth towards the 

 North Sea, must have pushed along the marine shells and silt which 

 it encountered on the sea-floor. These would be commingled with 

 the moraine profonde which had gathered underneath the ice-sheet ; 

 and the shells would ultimately be smoothed and striated precisely 

 like the stones in the bottom moraine. Hence the occurrence of Scotch 

 rocks together with shell-fragments in the Orkney Boulder-clay is 

 what we would naturally expect ; and in the light of the foregoing 

 reasoning all difliculty as to the explanation of the phenomena dis- 

 appears. It is not necessary for us to assign the precise localities 

 from which the various foreign rocks have been derived ; it is suffi- 

 cient for our present purpose if we show, as has been done, that 



