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The Naturalist. 



ordinary surface soil, a bed of coarse gravel is met with, composed of 

 local stones, under that there lies another, largely composed of local 

 pebbles, but having also a great quantity of what, for brevity, we term 

 " foreign boulders," consisting of granite, syenite, greenstone, trap, 

 slate, quartz rock, limestone, &c., none of which occur about here, the 

 nearest places being Westmoreland and Craven. The foreign boulders 

 were brought here during the great ice age," when the North of 

 England was covered by a vast sheet, or sheets, of ice, in the form of 

 many confluent glaciers, emanating from the high hills of the Lake 

 District, from the Scotch mountains, and the higher parts of the 

 Pennine chain, upon whose bosoms were borne immense quantities of 

 rock and debris, which were scattered far and wide over the North 

 and middle of England. Afterwards the country slowly sunk beneath 

 a boreal sea, and only the higher parts of the Pennine chain and other 

 hills stood above the sea level. During this period of submergence, 

 icebergs careered over the sea and deposited their burden of rock and 

 sand over the submerged land. After a time the land uprose again 

 out of the sea, and another set of local glaciers began to form on the 

 hills and upland valleys, which helped in a large measure to clear off 

 the hills and out of the higher dales the debris left by the former 

 glaciers and icebergs. We have evidence in this neighbourhood of 

 all these movements of the land and sea, of the great glacier ice field, 

 of the submergence of the land, of icebergs dropping their burden of 

 rock, and of the final uprising of the land above the sea, and of the 

 last local glaciers. That portion of the Pennine chain from Boulds- 

 worth Hill southwards, is, on the eastern side, remarkably free from 

 glacial deposits, while on the western side they rise to an altitude of 

 1,150 feet, and on some of the moors about Bacup they attain an 

 elevation of 1,400 feet. It is only of late years that Calderdale has 

 been known to yield these foreign boulders, and it is still a debatable 

 question as to which way they came here. To any person who studies 

 the topography of the Pennine chain, and the occurrence of glacial 

 beds at such great altitudes on the other side, it would seem an easy 

 matter for them to have come through passes such as Walsden and 

 Clivigir, and so down Calderdale. But the problem is not quite so 

 simple as that, for if they came in that way we should naturally 

 expect to find some evidences of them in those passes, but of all the 

 places in Calderdale these passes are the most barren in these 

 foreign boulders. You can mount the steep flanks of the hill on 

 either side of the Walsden pass at the western end, and trace these 

 boulders up to heights of 1,150 feet, while in the pass itself, which is 



