llt'trospective Criticism. *2?7 



a negative. Some of your readers may perhaps be able to give an opinion 

 more strongly confirmed by experience than mine would be. The valley 

 of the Swale, some miles above Richmond, is rich in veins of galena, and, 

 far from being " not uncommon," they constitute the entire wealth and 

 produce of the country. From that valley lead is forwarded to all the 

 Yorkshire markets and consumers, and from Stockton upon Tees great 

 quantities are shipped to London and the southern ports. 



Perhaps I may be ignorant of the meaning of the term " elevation " used 

 by T. E. L. in describing the " thickness " of the mountain limestone stra- 

 tum ; or science may have assigned to that polysyllable a different inter- 

 pretation from its common conventional one. T. E. L. makes the words 

 " thickness " and " elevation " synonymous. The passage is this : — "The 

 thickness of the mountain limestone varies ; perhaps we may not exceed 

 the mark in assigning it an elevation of 300 or 400 feet." It appears to me 

 that the latter member of this sentence does not explain the former ; since 

 the elevation or height of a substance can give no ciue to discover its 

 thickness. Here is an arithmetical problem, which will employ as much of 

 T. E. L.'s time to solve, as it would of mine to unriddle his observation : — 

 If the perpendicular height of a maypole be 60 ft., what will its diameter 

 be ? Perhaps T. E. L. will explain me this matter. 



The mountain limestone not unfrequently appears lying under the grit- 

 stone, as is the case at the outcrop at Ingleborough Hill, and Whernside 

 in Yorkshire. This latter hill, indeed, derives its appellation from the an- 

 cient household article in making which its gritstone was employed, namely, 

 the querTiy which by an easy corruption becomes whcrn. 



T. E. L. says " there are mrfew^ proofs of the valley [of the Swale] hav- 

 ing been narrower in former times." I should like him to give me his 

 reasons for such an evident conclusion. It never struck me as having been 

 likely, nor does it appear at all probable. Does T. E. L. mean by the 

 " basis of the hills " the land in the valley ? Some further remarks from 

 T. E. L. upon the " geography of plants," if gathered by his own-observ- 

 ation, and well supported by facts, would be interesting and instructive. 



My kind wishes for T. E. L.'s success as a naturalist have drawn me 

 into these remarks. I am in general so inert that nothing but liiy kind 

 feelings towards him, or some " such convulsion of nature," or " great acting 

 force," as hath formed a passage through the hills for the river Swale, and 

 dismembered the Round How from its parent rock (as T. E. L. describe 

 it), could have impelled me to scribble at such length, and with such pro- 

 lixity. — N. Januart/ 27. 1831. 



The specific Relations of Anagdllis arvensis and asrulea. — ■ Sir, In reply 

 to Professor Henslow's communication (Vol. III. p. 537.), I have to state 

 that, in 1828, a friend sent me a small parcel of seeds of ^nagallis caerulea, 

 from which I raised a considerable number of plants ; but not one of them 

 presented any thing different from the usual appearance of the plant from 

 which they were derived. I suffered the plants to scatter their seeds, and 

 the following year they came up equally numerous, but still without any 

 ■deviation. The above was not done with any view to ascertain the fact 

 of identity ; but had any variation occurred in the colour, &c., I should have 

 observed it, as I was very frequently looking at the plants. The soil upon 

 which they grew was gravel, with a slight covering of mould. It may be as 

 well to observe that we consider the Jnagallis caerulea a very rare plant; 

 indeed, I have never seen it wild, although Jnagallis arvensis, as in most 

 other places, is one of our commonest weeds. As blue flowers are subject 

 to more variation than others ; and as flowers of that colour and white 

 frequently turn to red in their last stage. Professor Henslow should have 

 stated if the flowers were red at first opening ; and if they were precisely 

 of the same colour as the ^nagallis arvensis. I presume every means was 

 used to prevent the introduction of the more common plant, which is so very 



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