Scientific Intelligence, — Geology. 207 



8. Reopening of' the Manganese Mine at Grandholm, near 

 Aberdeen. — We are informed by Dr Fleming that the ore w- 

 curs in a rock of mica-slate, which stretches in a northerly di- 

 rection, and has an easterly dip, varying from 30° to 50° and 

 upwards. In some places it is thin slaty, even, or waved, while 

 at other parts thin beds of gneiss and granite make their ap- 

 pearance. When the mine was opened upwards of twenty 

 years ago, an excavation, or opencast^ was made across the 

 stretch of the strata, at the eastern termination of which a mass 

 of felspar porphyry makes its appearance, the relations of which 

 are not seen at present. The ore, which is the " grey Manga- 

 nese ore,"" or " Hydrous Binoxide of Manganese," occurs in 

 irj'egular thin beds, rounded concretions or anastomosing films 

 in the rock, accompanied by small quantities of sulphate of 

 barytes. As the working has but recently commenced, little 

 more than a dozen of tons of the ore have been obtained. But 

 as the undertaking is in hands possessing abundance of capital 

 and enterprise, Messrs Cookson of Newcastle, the mine will 

 now have a fair trial, and it is hoped that a new branch of trade 

 will thus be added to those already so successftdly carried on 

 at Aberdeen. 



9. On the Formation of Calcareous Spar and Arragonite. — 

 M. Gustav Rose draws the following conclusions from a series 

 of experiments performed by him on this subject: — 1. That 

 in the humid way both calcareous spar and arragonite are 

 formed, the former at a lower, the latter at a higher tempera- 

 ture; but in the dry way calcareous spar only is formed. 

 % That the carbonate of lime, immediately after precipitation 

 from a cold solution, is in an indistinctly crystalline condition, 

 which resembles that of chalk, and from which the distinctly 

 crystalline condition afterwards proceeds. 3. That arragonite 

 can be very easily converted into calcareous spar, in the moist 

 way, by allowing the arragonite obtained by precipitation to 

 stand in water or in a solution of carbonate of ammonia; in the 

 dry way, by exposing the arragonite to a low red heat, when 

 the large crystals fall into a coarse powder, but the small 

 crystals retain their form and produce pseudomorphous crystals. 

 It results, moreover, from the investigations of M. G. Rose, 

 that the origin of arragonite cannot now be ascribed, as has 



