534 Henry Wood'wa7'd — Address to the Geologists' Association. 



met with. The iron has the composition Fck, Ni, and contains 

 a trace of copper. It is remarkable that this meteorite greatly 

 resembles those of Eittersgrtin and Steinbach, and it appears highly- 

 probable that they belong to the same meteoric fall which is believed 

 by the illustrious Breithai;pt (whose loss we have now to deplore) to 

 have been the " Eisen regen," that occurred at Whitsuntide, 1164, in 

 Saxony, when a mass of iron fell in the town of Meissen. 



Several hundred meteorites have also been cut, under the direction 

 of Prof. Maskelyne, and thin slices mounted for microscopic examina- 

 tion of their crystalline structure, a study which promises most 

 valuable results for Petrology. 



We have only space here to call attention in passing to a most 

 important paper by the eminent French chemist and physicist, 

 Prof. Daubree, on Meteorites and their composition, given nearly 

 in extenso in the Geol. Mag. 1866, VoL III. p. 362 and p. 414, and 

 a later notice on the Classification of Meteorites (Geol. Mag. 1868, 

 Vol. V. p. 75), both of which are deserving of careful perusal. 



Foremost among petrologists in tlris country must be mentioned 

 the names of Mr. David Forbes, F.E.S., and Mr. Henry 0. Sorby, 

 F.E.S., some of whose researches have already been made public in 

 the Transactions of the Eoyal Society and elsewhere. 



Mr. Samuel Allport, F.G^S., Prof. Haughton, F.E.S., and more re- 

 cently still Prof. Edward Hull, F-E.S. (Director of the Geological 

 Survey of Ireland), have been devoting much care and attention to 

 the microscopic investigation of igneous rocks and their constituent 

 minerals. The most recent of these relate to the investigation of 

 the Pitchstones and Felsites of Arran by Mr. Allport ; ^ and that of 

 the Limerick Traprocks and Irish Granites by Prof. Hull.^ 



An important step has been taken by the former writer towards 

 the demolition of that long-prevalent and once generally-received 

 doctrine that the eruptive rocks of Palaeozoic age were always distinct 

 in composition and structure from those of the Tertiary period. Mr. 

 Allport points out that great differences do certainly exist between 

 augitic lavas of different volcanic districts ; but he maintains that the 

 same is true of those of the older geological periods, and similar 

 differences occur between rocks of various ages. 



" Thus, by ignoring the distinction now made between rocks of dif- 

 ferent ages, when there is really no essential difference between them, 

 we should get rid of melaphyr, aphcmite, anamesite, diabase, and green- 

 stone. The three former are but varieties of ' dolerite,' ' diabase ' is 

 simply an altered 'dolerite,' while ' greenstone ' has now no definite 

 meaning whatever, having been applied to diorites, dolerites, felsites, 

 or in fact to any rock which a collector or writer could not make 

 out." 1 



(6.) Physical Geology (Mountains); — In traversing the surface of 

 our earth, or in crossing the waters of the ocean, we meet with forms 



1 S. Allport, " Igneous Eocks of Arran," Geol. Mag, 1872, Vol. IX. p. 544. 

 See also op. cit. 1873, Vol. X. p. 196. 



2 Prof. Hull, Geol. Mag. 1873, Vol. X. pp. 153 and 193. 



