332 Correspondence — Dr. C. R. Eastman. 



towards the north, and constitute a plateau of marine erosion sloping 

 to the north and east, covered with Drift, which is in places not less 

 than 450 feet thick. 



3, " Note on a Preliminary Examination of the Ash that fell on 

 Barbados, after the Eruption at St. Vincent (West Indies)." By- 

 John Smith Flett, M.A., D.Sc, F.E.S.E., F.G.S. With an Analysis 

 of the Dust by William Pollard, M.A., D.Sc, F.G.S. 



Two samples of the material were sent by Dr. D. Morris, of the 

 Imperial Agricultural Department for the West Indies, to Professor 

 J. W. Judd, who forwarded them to the Director of the Museum 

 of Practical Geology. The fine grey powder is gritty to the touch, 

 and it all passed through a sieve with 30 meshes to the inch. It 

 contains plagioclase - felspar (generally idiomorphic labradorite) 

 coated with a thin film of glass, hypersthene and monoclinic 

 brownish augite, both frequently in perfect crystals, magnetite, 

 apatite, possibly zircon, and fragments of a brown glass. Among 

 the finest debris there is much felspar in the form of minute chips. 

 The perfect crystalline form of many of the constituents of the dust 

 and the small amount of glass adherent to them, indicate that at the 

 time of projection the glassy magma must have been very fluid, and 

 it must have been to a large extent wiped off the crystals by friction. 

 From Dr. Morris's account the minerals of high specific gravity 

 appear to have fallen first; the order being magnetite and pyroxenes 

 first, next the felspars, and finally the glass threads and minute 

 felspar debris. Dr. Pollard's analysis is as follows : — Si 02=52-81, 

 Ti O2 = -95, Al, O3 = 18-79, Fe^ O3 = 3-28, Fe = 4-58, Mn = -28, 

 (Co Ni) = -07, Ca = 9-58, Mg = 5-19, K^ O = -60, Na^ = 3-23, 

 P2 O3 = -15, S O3 = -33, 01 = -14, H2 = -37 ; total 100-35. 



GOS-E-SSI^OIsriDElNrGJEl. 



FIGURES OF CAMFYLOPRION, PLATE VIII. 



Sir, — Owing to my not having had the opportunity to see proofs 

 of illustrations for my article on Campyloprion in the April number 

 of the Magazine, a slight error occurred in designating their scale of 

 reduction. Figs. 1 and 2 of Plate VIII are reduced to about three- 

 sevenths natural size, and Fig. 3 in the text is of the natural 

 size. In the Explanation of Figures on p. 152, the fused teeth 

 of Campyloprion are stated to be " supported at their bases by 

 a band of calcified cartilage." This should be understood as 

 an inference drawn from analogy, and not as implying that the 

 basal parts of the segments in this genus or in Edestus are of 

 calcified cartilage, when they have been well ascertained to consist 

 of vasodentine. C. E. Eastman. 



Museum of Comparative Zoology, 

 Cambridge, Mass. 



