My Dear Sir,

D^r Allan has got your last letter, and he has been for some weeks so much engaged from the prevalence of fever in the neighbourhood, and from the great people being all at their seats within his round, that I have not been able to get him at leasure and alone long enough to answer your enquiries. He dined with me the other evening and we had some interesting conversation— I had misunderstood him it seems about Aldabra being coral—it rather seems to be volcanic.¹ I was thinking so much of coral & had its fused aspect in Arabia so much before my eyes—but more of this when he answers your questions in detail. In the mean time I take advantage of an opportunity to send you all D^r. Hardie says of the Mecclesfield Bank in his notes. “Oct^r 10^th. 1830 On board the H.C.S. Errand, China seas. In Lat. 15.44’N Long 114^o.17’E over the Mecclesfield bank² sounding made this morning at 10 0’clock ^AM. depth 41 fathoms. The plummet having been prepared by filling up the hollow at its base with soft adhering matter; on hauling it up we found adhering to it numerous fragments of minute shells, and small portions of the axis of a variety of Polypifer,—all of them apparently perfectly fresh and recent. Traces of the fleshy incrustment of the Polypifer also observed, the axis of which was solid, stony, ramose, and of a coral red color.— Fragments too minute to admit of being characterized more correctly—they did not appear to be striated, and the axis had apparently been articulated by stony, somewhat spongy and tumid joints. M. Quoy in a paper read before the French Institute, July 1823 is quoted by Mr Scrope (Volcanoes P 185)³ as having stated the extreme depth at which “Madrepores” exist to be 30 feet; and Mr Scrope himself asserts that “the remarkable Zoophites which elaborate coral, never perhaps exist at a greater depth than a hundred feet.” The above statement appears to contradict the opinions quoted; it is also worthy of remark that on one or two occasions, fragments of solid rock were found adhering to the plummet even when the depth of water was greater than in the instance detailed. These consisted of fragments of coral cemented together by a calcareous cement. Fragments, angular and obviously recently fractured from a larger mass, in all probability by the force of the descending plummet. Mecclesfield Bank 300 miles distant from any land either continental or insular, and appears to form the “summit of an irregular submarine plateau of very considerable extent, upon which myriads of Zoofites are employed in rearing the foundations of a future island.” It extends according to Horsburgh,⁴ from Lat 15–17 to 16^o 21’ n “its breadth from E to W being about 70 miles. The depth of the water over the bank varies from 25 or 30 to 45 or 50 fathoms—coral rocks—but there appears to be gaps where no soundings are obtained. On the northern parts there are level patches of considerable dimensions with regular soundings from 9 to 15 fathoms sandy bottom. In one position only is the water so shallow as 8 fathoms.” Horsburgh contains much valuable information, and Allan adds his testimony to all others of his accuracy.—

I have a small parcel of the sand brought up from the Mecclesfield bank which I intended to have sent you, but have been unable to get time today to look out for it in a box of specimens I have not opened for some time. I shall send it next opportunity I had intended a longer letter and more to the purpose but having to send by this opportunity copies of a memoir on some forms of Liver disease I have recently printed, to some of my medical friends in India, I had to write so many notes, some of them increasing to letters, that I am quite tired.

I have had a long conversation to day with Mr Shiar, at present acting professor of Natural History at Aberdeen,⁵ on the species of trout known as Salmon Trout, & Whitling or Finnack. He laments the want of any treatise on the value of characters in fish—is positive that the number of vertebræ vary—but also that some confusion has arisen from a different system of enumeration. We are to dissect a number of these trout tomorrow—preserved with the view of some of them being sent to Agassiz agreeably to a promise I made to him.— A few remarks on this subject from you, would assist us in this enquiry. In walking across the Tuilleries Gardens with Agassiz, we stopped to contemplate the gold fish in one of the fountains. He remarked that they were Albinoe’s. I have some in my room and often look at them with interest—and speculate on this remark and how it is to be reconciled to their having such deep black pupils, while other animals so diseased have them red.

The only thing new recently found here, are two localities of the sandstone polished and grooved as described by Hall,⁶ Murchison in Sutherland,⁷ Agassiz⁸ and discovered by myself in Fyfeshire. I have also been examining a great (so called) submarine forrest (peat rather). It is a most interesting phenomenon, occupies the whole bay between Burghead and Findhorn, and is only seen at very low tides—yet I see no necessity for depression of the land to explain it. It strikes me as a difficulty to your erratic block theory the lines on the polished rock being all in one direction over such a great extent of country which also corresponds to the line of the erratics that can be referred to rocks whose position is determined. This is established I think on an extensive induction. I have not yet received your paper from London, and regret that I did not before my visit to Glen Roy, which was a hurried one the weather being very bad. I have Sir T Lauderdick’s paper and also McCullochs, and his 2^d . paper in the Edin^b. Encycloped⁠⟨⁠ia.⁠⟩⁠⁹ On this subject I shall write you when I get your paper. You will see a good abstract of it in the Scotsman newspaper Sep^r. 4^th 1839; and some remarks by the Editor—Mr M^c Laren author of a work on the Geology of the Lothians. He gives interesting geological notices especially of the raised beaches. But I must not trouble you with more of my scrawls | Yours sincerely | J. G. Malcolmson

I am in daily expectation of the Voyages of the Beagle from the Library in London to which I subscribe and shall make such notes as occur to me.— If you will look over the news in the August number of the “Asiatic Journal” you will see notice of flames from the hills inland from Assam, & cracks in the Earth at Ava. I hope we shall have a good account of these things in the Journal of the Asiatic Society of Bengal. I have written to a friend at Calcutta for references about the Chitagong volcanoes. Pray write a few lines if you have leasure