Page:Quarterly Journal of the Geological Society of London, vol. 32.djvu/262

190 Clough from the White well valley at an elevation of 1170 feet, and passing on east of Deerplay Hill and the high land adjoining into the valley of the Irwell, thence skirting the hilly district east of Bacup and crossing Brandwood Moor, the dividing line between the basin of the Roach and Irwell, and so continuing its course on to Manchester and the great Cheshire plain; whilst another stream of ice would doubtless cross from Burnley into the Whitewell valley by the Wholaw-Nook pass, becoming there confluent with the arm already described, the main body moving off in the direction of Burnley and Accrington, on the westerly side of Hambledon Hill, thence pursuing its course south and uniting with the other streams, finally debouching onto the plains of South Lancashire.

In support of the theory that a large body of moving ice meeting with resistance sufficiently powerful can be either entirely arrested, or its various portions be endowed with varying and diverse motions, we have the authority of the Duke of Argyll, Prof. Ramsay, and Mr. Goodchild, some of whose statements fully justify the conclusion that such was the behaviour of the ice in this instance.

In all probability ice did not overflow the higher hills in this part of the axial range, as is manifested by the absence of all trace of its action upon the surface-contour of the country, and by the fact that there are no remains of morainic or other matter to indicate that it had ever been in those situations.

It may be assumed that the great ice-sheet in this part of Lancashire did not rise to so great an elevation by some hundreds of feet as it is proved to have done further to the north by the observations of Mr. Tiddeman, Mr. J. Clifton Ward, and Mr. Goodchild; and I contend that satisfactory reasons may be given for this variation by taking into consideration the gradual slope of the ground, the waste by melting to which the ice would be subjected in travelling south, and its tendency to spread out and become diffused on reaching the flatter and more level plains of Lancashire and Cheshire.

Statements contained in the memoir by A. H. Green, C. Le Neve Foster, and J. R. Dakyns on the Geology of the Carboniferous Limestone, Yoredale Rocks, and Millstone Grit of North Derbyshire and the adjoining parts of Yorkshire, confirm many of these conclusions arrived at by me on independent grounds.

I have thus endeavoured to lay before the reader such facts as have come within my reach tending to illustrate the question forming the subject of this essay, with what success he will be able to judge. If, however, the facts and arguments should fail to carry conviction, I trust that the effort I have made to solve this somewhat difficult and perplexing question may not prove altogether fruitless; for should no other result follow than that of attracting the attention of other observers to the subject, so that eventually a satisfactory solution may be arrived at, my object will, at all events to some extent, have been attained.