1114 Asiatic Society. £No. 144. 



REPORT OF THE CURATOR MUSEUM OF ECONOMIC GEOLOGY. 



Report of the Curator Museum Economic Geology and Mineralogical and Geological 

 Departments, for the month of November. 



Geological and Mineralogical. — As we have been unable to despacth a scientific 

 geologist to visit the Cheduba groupe as at first recommended, all that could be 

 done was to frame a letter for the Captain of the Steamer, so as to enable him to do 

 the best he could in the way of collecting what he might meet with, and this he 

 has done very zealously. I have but just received his collection, and shall therefore 

 be obliged to delay my report upon it till I learn the localities visited, and other 

 particulars, but the following copy of our letter should be placed upon record : — 



Captain Russell, Commanding H. C. Steamer Ganges. 



Sir, — As it is not improbable that much preliminary geological, and even some 

 mineralogical knowledge may be obtainable by yourself and Officers on your ap- 

 proaching survey trip to the Straits of Cheduba and adjacent Islands, I have been de- 

 sired by the Honorable the President of the Asiatic Society, to point out to you briefly, 

 how this may be best accomplished. 



Geological. — Your first object is, I believe, to ascertain what traces, as shoals, &c. 

 may remain of the Volcanic Island, which recently rose and disappeared off the S. E. 

 point of False Island, near Cheduba. If the place of the new island can be correctly 

 ascertained, and the water be not too deep, specimens of the scoriae and mud should be, if 

 possible, obtained by dredging and diving, with as many shells, stones, &c as can be had, 

 particularly if with marks of action of fire. A 6-dozen wine chest full of these or more 

 will be none too many, if there are many kinds, and the more variety the better. 



Whether the Volcanic shoal has any connection with* the reef to the South of False 

 Island or not, specimens taken up to the dry reef and the shores of the island, should also 

 be collected ; the island itself should be carefully examined and a section of it taken, if 

 possible, numbering or marking all the varieties of rocks, soils and corals, &c. &c. to 

 correspond as A, B, C, &c. The names you give to the stones or rocks, do not signify in 

 the least. You may call them any name you like, but the points are their exact place, 

 and how the beds of them lie, if the lines of beds can be seen, as thus : — 



" L. No. 1 to 7. — Hard blue stone ; beds slope with their faces to the S. E. and are ele- 

 vated about 30° from the sea horizon, the line of the faces of the beds lies N. and S.* 



M. — Confused masses of yellow, dark brown, and black stone and boulders with shells, 

 no beds to be made out. 



N. — Level beds of soft sandstone much worn by the sea," and so forth : noting imme- 

 diately every specimen or lot of specimens as obtained. 



The other small Islands should also be visited and examined in like manner. 



Traces of elevations are, according to Captain Halstead, every where to be seen on 

 Flat Island, in beaches of shells at different heights, particularly at " Square Rock," 

 (see his chart.) A good description with plenty of specimens from this rock and the Island 

 would be very desirable. These should be described, measured, and plenty of specimens 

 brought from them, as well as from the present beach ; not only to enable us to judge 

 of the number of risings, but also if there have been sinkings again between the dif- 



* This is called the dip and the strike of rocks, or mineral beds, or strata. 



