Mr. P. I. Martin's Observations on the Anticlinal Line, 4-c. 1 1 1 



reader's time by quoting the opinions of Otto'^Guerlcke, Buf- 

 fon, Bouguer, Melville and others, on blue shadows ; as they all 

 accounted for blue shadows on the Newtonian theory, and 

 never dreamt that a black shadow could be changed into all 

 the colours of the rainbow, supposing that the fainter rays were 

 stopped in the atmosphere, and the blue reflected. Some years 

 aero, when writing the "Experimental Outlines," I had not at- 

 tended to this part of my subject sufficiently, therefore could 

 not account satisfactorily for the green which BufFon saw on 

 the garden wall at sun-set. This I now find proceeds from 

 the overlapping of blue and yellow shadows rarefied by the 

 light of the sun, and light reflected from the clouds, or the cliff" 

 of the mountain. As these philosophers were involved in a 

 labyrinth as intricate as that of Rosamond's Bower, and from 

 which no clue could ever extricate them, — I shall not attempt 

 to follow them any further. I am, &c. 



Joseph Reade. 



XVIII. Observations on the Anticlinal Line of the London and 

 Hampshire Basiiis, Sfc. By P. I. Martin, Esq* 



HAVING been lately engaged in an attempt to combine 

 some of the evidence of the conjunctive operations of 

 derangement and denudation in the formation of what are 

 called the Basins of London and Hampshire, in a theory 

 which I judge to be applicable, with some modifications, to 

 almost all trough- or basin-shaped contortions of strata that 

 have a conformable disposition ; it may not be uninteresting 

 to follow up the research with some observations naturally 

 arising out of the subject, and which merit consideration, not 

 only as confirmative of the theoretical opinions there deve- 

 loped, but also as highly illustrative of the problem so in- 

 teresting to all the lovers of Nature, — the modification of the 

 present surface of the globe, and the acts and agencies by 

 which it has been effected. 



In my Essayf on the Formation of the Valley of theWeald, I 

 have attempted, in following up the ideas of Dr. Biickland and 

 Mr. Scrope, on Valleys of Elevation, to show, that the protru- 

 sion of an " anticlinal line " between the Basins of London 

 and Hampshire, or, which is tantamount to it, the depression of 

 tlie parts constituting those basins across a fixed point, burst 

 or broke up the intervening ones, and gave rise to the basins 

 and to the valley of denudation which lies between them ; 



* Communicated by the Author. 



t " A (ifological Memoir on :i part of Western Sussex, &c'." fiOn- 

 don, 1828. 



and 



