440 THE NATUEAL HISTORY EEVIEW. 



ageni;^, and it was therefore inferred that the amount of decom- 

 position in veins and in rocks is proportional to the amount of 

 their elevation above the sea, Mr. Wallace then stated that Arra- 

 gonite is produced only after the strata are traversed by joints, 

 and that the branched Arragonite very rarely occurs, being found 

 only in caverns and old workings. Two of these caverns have 

 come under his notice, and were described in detail ; one of them 

 is in the north vein of the silver Band Mine, and the other near 

 one of the principal veins of the Dufton Eell Mine. Einally, he 

 discussed the causes and conditions necessary to the formation of 

 this Coralloidal Arragonite, and came to the conclusion that the 

 theory of a circulation, through the pores of the spar, of fluids hold- 

 ing its component parts in solution, is the only one that harmonizes 

 with the varied phenomena observed in the two caverns he had 

 described, 



3. " Notes on Presenting some Ehomboidal Specimens of Iron- 

 stone, &c." By Sir J. W. E.Herschel, Bart., K.C.H.,r.E,S„ E,G-.S., 

 &c. With a Note by Captain T. Longworth Dames. Communicated 

 by Sir C. Lyell, Bart., r,E,S,, F.G.S.— Most of these specimens 

 came from a quarry at Clanmullen, near Edenderry, King's County, 

 and the remainder from the Collingwood Quarry, in the Weald of 

 Kent. The Irish specimens are siliceous, containing some oxide of 

 iron and a little manganese, and are homogeneous throughout. They 

 all agree in the sharj^ness of definition and the exact parallelism and 

 evenness of the flat surfaces; but, like those from the Weald, they 

 are not constant in form or size, and sometimes are very irregular in 

 angle and in the parallelism of opposite sides. The Wealden 

 specimens, however, are all closed boxes, each containing a rhomboid 

 of hardened sandstone, the outer case being highly ferruginous — in 

 fact, the " Ironstone of the Weald." Sir John Herschel endeavoured 

 to account for the formation of the boxes, and Captain Dames added 

 a note stating the circumstances under which the Irish specimens 

 occur. 



May 10th, 1865. 



The following communications were read : — 1. " On the Azoic 

 and Palaeozoic Eocks of Southern New Brunswick." By. G-. F. 

 Matthew, Esq. Communicated by Dr. J. W. Dawson, E.E.S,, 

 E,G.S. — After briefly narrating the History of the Geology of the 

 Kegion, the author described each of the formations successively in 



