Mr. R. C. Taylor on the Geology of Cuba. 17 



gested to me the probability of detecting structure in the ashes 

 of coal; and, upon examination, I find that the white ashes of 

 " slaty coal " furnish most beautiful examples of vegetable re- 

 mains. We have thus additional evidence that the basis of 

 vegetable structure is independent of carbon. 



Explanation of the Figures. (Plate I.) 



Figs. 1,2,3. Skeletons of portions of recent plants. 



1. Part of husk of Oat, with separate drawings of the cups, which 



are attached at nearly uniform intervals along the siliceous 

 columns. 



2. Part of leaf of the Iris. 



3. Hair of leaf of Cornus alba (Common Dogwood). 



Figs. 4, 5, 6, 7. 8. Siliceous skeletons of portions of plants occurring abun- 

 dantly in the white ashes of coal. 

 4,5. Cellular structure. 



6. Annular ducts with transverse bars. 



7. Spiral fibre. 



8. Fibre in situ. 



Magnifying power about three hundred linear. The parallel siliceous 

 lines of the Oat, occurring in some cases at intervals of l-4000dth of an 

 inch, form a very delicate natural micrometer. 



P.S. Since writing this paper, I have been indebted to Mr. Brown's 

 kindness for the perusal of Struve's Inaugural Dissertation, " De Silicia in 

 Plantis nonnnllis." It is the author's object to show that pure sillica forms 

 the skeleton of three species of Equisetum, and also of the Spongia lacustris 

 and Calamus Rhodan. I am gratified by finding the following remark : " Sub 

 aeris libero aditu ustis, restat sceleton, totam plantae form am accurate ser- 

 vans, partibus animalium osseisquam maxime comparandum." p. 12. 



My attention has also been directed to Mr. Lyell's observations on 

 Goppert's Memoir on the Process of Lapidification, Phil. Mag., May 1837, 

 p. 408, and Ehrenberg's Memoirs on Fossil Infusoria, Scientific Memoirs, 

 vol. i. part iii. 



IV. Notes relative to the Geology of a Portion of the District 



of ' Holguin in the Island of Cuba, and the Mineral Region 



on the North-east Coast, from the Observations of himself 



and Thomas G. Clemson, Esq. By Richard Cowling 



Taylor, Esq., F.G.S., fyc.* 



W/*E have prepared a detailed description of the mineral 



** region in the vicinity of Gibara, and particularly as to 



its copper lodes ; but as some delay will unavoidably take 



place in its publication, I have arranged a portion of our 



notes as a preliminary communication to the Philosophical 



Magazine. 



A considerable portion of the year 1836 was devoted to an 

 examination of the north-east part of this island, a mineral 

 region which, so far as I can learn, has never been visited for 

 scientific purposes, and till recently has never been investigated 

 for the practical objects of mining. 



* Communicated by the Author. 

 Third Series. Vol. 11. No. 04. July 1837. D 



