44 



HARDVVICKE'S SCIENCE-GOSSIP. 



latter is the Xanthiunt spinosum, introduced from 

 Europe, the aclienes of which cling to the wool 

 with such tenacity that it is almost impossible to 

 detacli them, and render it almost unsaKable. It 

 spreads with such rapidity that in some parts legis- 

 lative enactments have been passed for its extirpa- 

 tion ; and where this is not done, it almost usurps 

 the place of the more useful vegetation. The 

 President (Mr. George Bentham) stated that the 

 Xantldum has in the same manner deteriorated the 

 pastures in Queensland ; whilst in the south of 

 Europe, where it is equally abundant, it does not 

 appear to cause such injurious results. Though 

 generally distributed through Europe, the plant is 

 probably of Chilian origin. 



Vegetation of Bermuda.^ — Mr. H. N. Moseley, 

 one of the naturalists to the Challenger expedition, 

 has recently communicated a paper on this subject 

 to the Limucin Society. He states that about 160 

 species of flowering plants were gathered on the 

 island, but of these not more than 100 were cer- 

 tainly native. Those of West-Indian origin were 

 probably brought, as Grisebach had suggested, by 

 the Gulf Stream or by cyclones, there being no 

 winds blowing directly from the American coast 

 which would be likely to carry seeds, which might, 

 however, be conveyed from the continent by mi- 

 gratory birds. A note by Professor Thiselton-Dyer 

 appended to the paper stated that 1G2 species sent 

 over by Mr. Moseley had been determined at the 

 Kew Herbarium, of which 71 belong to the Old 

 World, while two, an Enjthraia and a Spiranthes, 

 were plants hitherto known as confined to single 

 localities in the United States. 



GEOLOGY. 



Mode of Occurrence of the Diamonds in 

 South Africa. — In a paper on this interesting 

 subject just read before the Geological Society of 

 London by E. J. Dunn, the author stated that the 

 diamonds of South Africa occur in peculiar circular 

 areas, which he regards as "pipes," which formerly 

 constituted the connection between molten matter 

 below and surface volcanoes. The surrounding 

 country consists of horizontal shales, through which 

 these pii)es ascend nearly vertically, bending icp- 

 wards the edges of the shales at the contact. The 

 rock occupying these pipes was regarded by the 

 author as probably Gabi)ro, although in a very 

 altered condition. Intercalated between the shale- 

 beds there are sheets of dolerite, &c., and dykes of 

 the same rocks also intersect the shales at frequent 

 intervals. Within the pipes there arc unaltered 

 nodules of the same dolerite. With regard to the 

 relation of the diamonds to the rock of the pipes in 

 which they are found, the author stated that he 



thought it probable that the latter was only the 

 agent in bringing them to the surface, a large pro- 

 portion of the diamonds found consisting of frag- 

 ments. At the same time he remarked that each 

 pipe furnished diamonds of a different character 

 from those found in other pipes. 



The Mineral Wealth of Virginia. —The 

 recent opening of the Chesapeake and Ohio railway 

 from Richmond, on James River, to Huntington, on 

 the Ohio, and the consequent laying open of a large 

 tract of country hitherto almost inaccessible, has 

 directed much attention in the United States to the 

 resources of a district perhaps the richest and most 

 valuable in mineral wealth of any in America. The 

 railway crosses, at an oblique angle, several parallel 

 belts of useful minerals. Near Richmond is a triassic 

 coal-field long known and worked, though the coal is 

 not first-rate and the expense of getting is consider- 

 able. To the west of this belt is a large deposit of 

 iron pyrites, much of it auriferous. Still further 

 west is Charlottesville, where the C. and O. rail- 

 way is crossed by another of older date, abounding 

 on both sides with some of the purest and finest 

 magnetic oxides of iron known. These ores are 

 very free from all injurious mixtures. A little 

 further west there are several bands, or rather one 

 band presented in several folds of exceedingly pure 

 and rich brown hematites. Parallel with these is 

 another line of railway, partly opened, connecting 

 with the north. After an interval of 100 miles we 

 come upon the coal-measures. The lower part con- 

 tains a few good seams, but the middle part is 

 exceptionally rich and valuable. There is here 

 about 60 feet of coal in several workable seams, 

 and a thickness of less than 300 yards of measure. 

 The seams are intersected by the deep and pic- 

 turesque gorge of New River and the Kanawha 

 and reached by numerous tributaries. They can be 

 worked with great ease at small cost, and no coals 

 in the world can be better adapted for the coal- 

 cutting machine. Some of the seams have been 

 opened and are in moderately active work, yielding 

 three kinds of coal,— splint, a hard variety, well 

 adapted for steam and marine engines ; cannel 

 greatly valued for enriching gas ; and a moderately 

 rich bituminous coal, good for household use, and 

 believed to make excellent coke for iron-making 

 and locomotives. All these minerals are capable of 

 being worked as soon as the coal-fields are open, 

 and it is satisfactory to know that measures are 

 being taken to do this, and that English capital is 

 being diverted in this direction. One English 

 company has already started, and a branch rail is 

 being constructed to enter the coal-seam and carry 

 the mineral to the main line of the Chesapeake and 

 Ohio railway. The coal is here about 150 miles 

 from the iron ore, and iron can certainly be made 

 for a price not exceeding 60s. per ton, either where 



