Rocks with Plants, 343 



vegetation is likewise peculiar, entirely different from that of 

 the contiguous hills. These are invariably clothed with the 

 heaths ; but the tract just mentioned derives its name (Green 

 Hill) from a covering of grass. It produces Arenaria verna, 

 Cochlearia officinalis, and Statice Armeria ; of which the last 

 two are very rare in that quarter : as to Arenaria verna, I 

 never met with it in that part of Scotland, unless on the spot 

 mentioned ; and again in the parish of Leslie, growing over 

 serpentine, the same rock with which it is associated at 

 Strathdon. 



Though this communication may be already quite long 

 enough, I wish to occupy a few sentences with a notice of 

 remarks, in this Magazine, upon some observations made by 

 me at a previous period. In the first place, my thanks are 

 due to Mr. Thomson, Manchester, for his courteous and in- 

 teresting observations, in Vol. III. p. 410 — 419. Mr. Loudon 

 has likewise, with reference to me, made a few remarks, of a 

 fair and judicious description, in Vol. V. p. 195.; and there 

 (p. 196.) directed my attention to a contributor of a very 

 different stamp, who writes in Vol. IV. p. 460., under the sig- 

 nature of Causidicus. I may be permitted to copy a couple of 

 sentences, as being the origin of the strictures of this writer : 

 — "I venture to suggest, that there is not, in science, a more 

 hopeless labour, than the attempt to discover an unvarying 

 and necessary relation between most plants and the chemical 

 nature of the soils in which they spontaneously grow. I 

 feel convinced that, except in point of moistness, compact- 

 ness, and depth, soils have in general no cognisable relation 

 to their native products." I shall not offer a detailed notice 

 of the remarks of Causidicus, but content myself with request- 

 ing your readers to refer to them ; and I shall be satisfied 

 that the cause be judged upon his own pleading. I may, 

 indeed, just quote his opening sentence relative to me. " The 

 first point whereon I should differ from Mr. Thomson would 

 be, the apathetic calmness, and almost scepticism, with which 

 he treats that most extraordinary hallucination of Dr. Alex- 

 ander Murray, which prefaces Mr. Thomson's remarks." 

 This passage (which alludes to the opinions above quoted) 

 may be considered a pretty fair specimen of the whole article. 

 The meaning of the sentence no one can positively tell ; and 

 the meaning which it may be guessed to have is entirely 

 devoid of foundation, as Mr. Thomson's allusion to me is of 

 a complimentary description. With respect to the " hallu^ 

 cination," I shall not say much on that head, as no one can 

 be considered the best judge of whether or not his own opi^ 

 nions deserve this epithet. I shall, however, observe that 



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