184 Correspondence. 



neighbourliood of Manchester,"^ That this similarity may be made 

 more apparent I here place the two series in juxta-position. 



Dktft Deposits of the North-'Westeiin and Eastern Counties. 

 A". W. Counties. Eastern Counties. '*■ 



3. Upper Boulder-clay, or Till. 3. Upper Drift (Boulder-clay). 



2. Middle sand and gravel. 2. Middle Drift (sand and gravel). 



1. Lower Boulder-clay, or Till. 1. Lower Drift (Boulder-clay) . 



I see that Mr. Maw, in the March number of the Geological 

 Magazine, endeavours to show that the above is not the true order 

 in time of the Lower and Upper Boulder-clays in the Eastern Coun- 

 ties ; but he allows that the evidence is not conclusive, as the true 

 relations of the coast Boulder-clay (1) and the high-level Boulder- 

 clay (3) have not been laid open to inspection ; but from his own 

 account I should conclude that the evidence is in favour of Mr. 

 Wood's classification, as he says, " there are very many instances of 

 the coast Boulder-clay being capped with gravel, and of the Boulder- 

 clay of the high ground being super-imposed on a subjacent gravel 

 bed. ; it must be admitted that these gravel beds correspond, in 

 height, and in many cases present the appearance of continuity, 

 but proof of their identity seems to be wanting." I should say from 

 the above, that if the proof is wanting, the evidence is very strong. 



Any evidence which shows the sequence in the Drift deposits on 

 the opposite sides of England to be similar is of such value, and is 

 so great a stride towards simplifying our knowledge of the quatern- 

 ary beds, that I, for one, sincerely hope Mr. Wood's classification 

 wdl ultimately be established beyond the possibility of a doubt; 

 and as regards the succession in Lancashire and Cheshire given 

 above, more extended investigations made since my paper was 

 written, have confirmed me in the belief that it is a real and widely- 

 extended sequence of deposits of the Glacial period. 



I am, etc., 



Edwakd Hull. 



THE OEIGIN OF ESCARPMENTS. 

 To the Editor of the Geological Magazine. 



SiK, — May I beg the insertion of a few observations upon a letter 

 by Mr. Mackintosh which appears in your Magazine for March. 



It will be remembered that Mr. Mackintosh, in the interesting 

 articles which first invited discussion in your pages, repeatedly 

 declared his belief in the marine origin of escarpments, and as 

 frequently referred to "terraces," etc., thereon which were thought 

 to support his views. Bearing this in mind, I was a little surprised 

 to find the following admission in his letter of last month, " These 

 longitudinal valleys and basins, which are not open plains, and which 

 often occur in what must once have been land-locked situations, appear 

 the more mysterious the more frequently they are contemplated." 

 I think Mr. Mackintosh must admit that marine action would be 

 wholly unable to erode continuous lines of clifi's in " land-locked 



1 Mem. Lit. and Phil. Soc. of Manchester, vol. ii. third series, 1863-4. 



