Correspondence — A/r. R. H. Tiddeman. 39 



outside chalk ridges, and one inside Weald Hill. And that these 

 three ridges of hills were as much formed by rain and rivers, as the 

 statue is formed by the sculptor. 1 thought that this was quite 

 simple. Mr. Mackintosh's receipt is more simple still. He first 

 brings in fire to make " longitudinal cracks during axial elevation," 

 then water in the form of currents " deflected and reflected so as to 

 hollow out the curvilinear ' coves' by which the ' capes' are separated. 

 But suppose it could be shown that powerful currents operating at a 

 considerable, not ' too great' a depth, are incapable of scooping out 

 the depressions bounded by escarpments, it would not be more in- 

 consistent with uniformity to suppose a cyclically-recurring intensi- 

 fication of the action of currents caused by sudden upheavals of 

 strata (here we have fire and water together) than to admit occa- 

 sional strides constituting breaks in the otherwise continuous series 

 of (organic) changes." 



This seems so probable that if I remain of the same opinion still, 

 it can only be from being convinced against my will. 



In the same number of your Magazine, page 568, Mr. Hull says, 

 ''I adopt, though with some hesitation the views of Professor Kam- 

 say, Dr. Foster, and Mr. Topley, regarding the subaerial denudation 

 of the Weald." If Mr. Hull will do me the honour to read the chapter 

 on the Weald in " Rain and Rivers," I think that he will do me the 

 justice to say that the above-named gentlemen have " adopted" my 

 principles, first published in 1853, and again in 1857. 



George Greenwood, Colonel. 

 Brookwood Park, Alresford, 

 6 December, 1867. 



THE VALLEYS OF LANCASHIRE. 



Sir, — My friend and colleague Mr. Hull in the last number (page 

 568) has again brought forward and endorsed his views as to the 

 formation of the valleys of Lancashire. As I have now for some 

 time been at work in North-East Lancashire and the adjoining parts 

 of Yorkshire, my silence would imply that the country on which I 

 am engaged bears evidence in favour of his views, whereas the facts, 

 so far as my experience goes, tend towards an opposite conclusion. 



He says '' Most of the valleys are really double valleys, the smaller 

 being alone due to river denudation, and the evidence of this lies in the 

 fact that, the larger, or primary, valleys are filled with terraces of 

 Marine Boulder-clay, and are really plains of marine denudation in 

 their earlier stages." (The italics are mine.) The fact I can 

 corroborate with pleasure, but I must difier from him in the in- 

 ference. I find myself obliged to go further than my friend and 

 state, that in the district, with which I am acquainted, the Boulder- 

 clay lies also in the "secondary" valleys, and in water-courses of 

 every size and at different levels (even in some of the narrow doughs 

 down the hill-sides), in short, in many of those " channels and fur- 

 rows," which Mr. Hull admits to have been formed " by the action 

 of frost, rains, rivers, and glaciers." In fact many of the brooks of 

 this part of Lancashire are simply re-excavating and enlarging fossil 



