TRACES OF THE GREAT ICE AGE IN DERBYSHIRE. 23 



Britain into a westerly direction, and scattering rock fragments 

 from the eastern counties over the midlands. In the early 

 portion of the glacial period the mountains of Britain formed 

 centres from which glaciers radiated, these at last becoming 

 confluent, and debouching upon the coast. It will be seen that, 

 from its physical character, the Irish Sea would form an 

 interesting region. In the earlier part of the period, the ends 

 of the glaciers broke off, forming icebergs ; but later, the Irish 

 Sea was completely filled with ice. An ice-sheet moved south- 

 wards from Galloway, becoming confluent with one from the 

 mountains of the Lake District and one from Ireland. Glaciers, 

 too, descended from the mountains of Wales, and the northern 

 part of the Pennine Chain. Anglesea and the Isle of Man were 

 completely overridden by the ice. 



Turning to Derbyshire, we find the traces of this cold period 

 of great importance, though less abundant than in the counties 

 to the north. Within the county the evidence is almost confined 

 to deposits of boulder-clay and erratics. Of the glacial striae, so 

 common in Scotland, Cumbria and Wales, we have none. It is 

 true it has been suggested that the boss of rock called the 

 " Bloody Stone " (on the foot-road between Cromford and 

 Bonsall), is a glaciated rock. Sir Andrew Ramsey, who visited 

 this stone, declined to accept it as a glaciated rock, although he 

 said that in a well-glaciated country it would pass muster as 

 such. * The writer has visited and examined this stone several 

 times, and is satisfied that the grooves and striae are not of 

 glacial origin. The rock is, presumably, more exposed than 

 formerly. However this may be, the striae may, in places, be 

 seen to dip into the rock, and doubtless, if the rock were cleaved, 

 would be found inside. This structure, which closely simulates 

 glacial markings, is not uncommon, and similarly marked boulders 

 may be found on the footpath between Ambergale and Crich. 



But we need not be surprised at the absence of glacial 

 markings on rocks in situ. It is not near the terminations 



"Geological Survey .Memoir for North Derbyshire," p. 92. 



