Notices of Memoirs — The Salt Mines of Prussia. 215 



the case in the Lake-district, and there does not appear to be a well- 

 marked series of trappean rocks at the base of the group, as there is 

 in many parts of the main area. As regards the character of the 

 Slates themselves, they are in many respects undistinguishable from 

 those of the Lake-country, but they are much finer grained than the 

 latter are as a rule, and there appears to be a total absence of breccias 

 and amygdaloidal ashes. 



The traps differ more conspicuously from those of the Lake-district, 

 though the latter would yield examples in all respects undistinguish- 

 able. I may instance especially the greenish-gray trap which 

 usually forms the base of the Green Slate series in the Lake-district, 

 as seen at Keld Beck near Shap, (in many places this bed departs 

 from these characters, and becomes highly hornblendic). Speaking 

 generally, the traps of the Ingleton section have a much greater 

 sameness than those of the Lake-district ; they are finer-grained ; 

 and they are much less often porphyritic. They are likewise much 

 less hornblendic than the majority of the traps of the Lake-moun- 

 tains, and tl^ere is nothing like a genuine diorite or amygdaloid. 

 The presence of free quartz in one of the Ingleton traps is noticeable, 

 since in the Lake-district this is only the case with the intrusive 

 rocks, and does not occur in any of the interbedded felstones with 

 which I am acquainted. 



The fossiliferous shales, which complete the section here, may be 

 the equivalent of the " Dufton Shales " of the Lake-district, or they 

 may represent the Coniston Limestone, the latter view being, per- 

 haps, the most probable, since they effervesce freely with acids. 



The apparent thickness of the Green Slates and Porphyries in the 

 Ingleton section is stated by Mr. Hughes to be about 10,000 feet, 

 but I should be disposed to believe with that observer, that there 

 must be a repetition of some of the strata by a fault or by a con- 

 cealed fold, either of which it would be very difficult to detect 

 owing to the sameness of the beds, the prevalence of cleavage, and 

 the absence or indistinctness of bedding. 



The Salt Deposits at Stassfukt, in Prussia. 



At a meeting of the Chemical Section of the Glasgow Philosophical 

 Society, held on January 18tli, Messrs Bald and MacTear communi- 

 cated a paper on the Salt Deposits at Stassfurt, The southern part 

 of the North German basin is divided by the Hartz into two portions, 

 known as the Thuringian and the Magdeburg Halbertstader basins, 

 in which salt has been raised for a lengthened period. 



In the Magdeburg basin the salt rests on New Eed Sandstone ; in 

 the Thuringian basin on Muschelkalk and Magnesian Limestone. 

 Stassfurt is situated in the Magdeburg basin. Here and at Erfurt 

 the Salt is mined, at all the other places in the district it is obtained 

 by means of brine wells. 



