Correspondence — G. H. Kinahan, Prof. Hull. 287 



RED ROCKS OF TYRONE AND DERRY COUNTIES. 



Sir, — From Mr. Ketley's paper on the coals under the "Bed 

 Bocks " of South Staffordshire, we learn tbat the Coal-measures under 

 certain circumstances may be made up of red strata, and that it is 

 erroneous to class all such red rocks as Permian or New Bed 

 Sandstones. 



In the Counties Tyrone and Derry there are some of these doubtful 

 aged rocks. The highest of them under the Chalk, called "Bedfre," 

 seem to lie unconformably on the others, and probably to belong to 

 the New Bed Sandstone. The older ones were in part classified by 

 the late General Portlock as Old Bed Sandstone, and in part 

 as Carboniferous, but now the general belief seems to be that they 

 belong to the Permian. During a brief examination of the country 

 made some time since, I found in places among the Coal-measure 

 rocks (which I supposed to be the equivalent of the lower Scotch 

 Coal-measures, such as occur in the neighbourhood of Edinburgh) 

 considerable tracts of these red strata, which led me to suspect that 

 most, if not all, these red rocks of the Counties Tyrone and Derry are 

 portions of the associated Carboniferous rocks. Time, however, did 

 not allow me to investigate the country minutely. In favour of 

 their being Permian, there are fossils said to belong to the Permian 

 type, that have been found in at least one locality ; but are not these 

 so-called Permian fossils very like stunted and ill-favoured forms of 

 the Carboniferous fossil s, and like what we might expect to meet in 

 those portions of the Carboniferous sea, where the water was im- 

 pregnated with iron or some other substance adverse to the growth 

 and proper development of animal life ? G. H. Kinahan. 



THE VOLCANIC DUST OF BARBADOES, 1812. 



Sir, — When reading the interesting paper by Dr. Flight on the 

 "History of Meteorites" 1 in the April Number of the Geological 

 Magazine (p. 159), I found a reference to the composition of the 

 Volcanic Dust which fell on the Island of Barbadoes during the 

 great eruption of the volcano of Le Souffrier, in St. Vincent, in 

 1812, described by Humboldt, and more recently by Lyell, 2 Daubeny, 3 

 and Scrope.* Having just received some of this dust, placed in my 

 hands for microscopical examination, — which had been collected by 

 a relative of mine 5 at that time resident in Barbadoes, — I have 

 thought it may be worth while, to note the results. 



It may be as well to premise, that this eruption was preceded by 

 the great earthquake of Caraccas in Venezuela, 6 which commenced on 

 the 26th March of the same year, and was felt all along the valley of 

 the Mississippi and the West Indian Islands. The eruption of Le 

 Souffrier took place about a month afterwards, namely, on 27th 

 April, opening by a grand discharge of ashes, which commenced to 



1 Dr. Flight's articles on Meteorites commenced in Geol. Mag., Jan., 1875. 



2 " Principles of Geology," vol. ii. 3 Daubeny, Volcanos, 2nd edit. p. 469. 

 4 Scrope on Volcanos, p. 432. 5 The late Mrs. C. T. Cooke, of Cheltenham. 

 6 See Geol. Mag. 1871, Vol. VIII. p. 348. 



