﻿90 



GEOLOGICAL MEMOIRS. 



fragments of Inocerami, large Ostrcece, &c, which, together with 

 the geographic position of the beds, agree perfectly with the rocks of 

 the Gahnsbauer. 



It has not been in the power of the authors to compare the Num- 

 mulites so often cited as occurring in the Gosau beds. The Vienna 

 collection does not contain any specimens ; but perhaps it would not 

 be too hazardous to conjecture, that in that case also Nummulites 

 have been confounded with Orbitulites [OrbitoidesT], and that in 

 the Eastern Alps Nummulites are not found in the chalk formation. 



[J. C. M.] 



On the Presence of Alkalies and Phosphoric Acid in some 

 Limestones. By Herr Fehling. 



[Wiirtemb. naturw. Jahresb. t. v. p. 72 et seq. ; and Leonhard u. Bronn's 

 Jahrb. f. Min. 1850, p. 445.] 



The results of the researches made by Faist agree on the whole with 

 those obtained by Schramm ; in all limestones alkalies were found to be 

 present, combined either with hydrochloric, or for the most part with 

 carbonic acid. Ten limestones gave decided and often very strong 

 evidence of the presence of phosphoric acid : — Jura-limestone from 

 Unterkochen and from Hundersingen ; Dolomite from Jaxtfeld (up- 

 permost bed of the Friedrichsthal limestone) ; Lias-limestone from 

 Rohr near Vaihingen ; Jura-marl from the Geisslinger Steige (above 

 the first Sponffites-bed) ; Keuper-limestone from the Weinsteige ; 

 Amalthei-c\a.y from Jesingen near Kirchheim ; upper Posidonomyce- 

 schist from Ohmden ; argillaceous Limestone from Blaubeuren; and 

 argillaceous Muschelkalk from Zuffenhausen. There was no phos- 

 phoric acid reaction in the Diluvial-limestone of Cannstatt, the Lias- 

 marl of Vaihingen, and the Carrara marble. [T. R. J.] 



On the Identity of Arkansite and Brookite. 

 By C. Rammelsberg. 



[Poggend. Annal. d. Phys. t. lxxvii. p. 586 et seq.', and Leonhard u. Bronn's 

 Jahrb. f. Min. 1850, p. 453.] 



Dr. C. U. Shepard some years since gave the first account of Ar- 

 kansite, discovered at Magnet Cove, Hot Springs County, Arkansas*. 

 According to the author, the crystals of the mineral examined by him 

 quite agree externally with Dr. Shepard' s description. The specific 

 gravityf he found to be=3*892, 3*923, 3*949, and in a chemical 

 analysis the Arkansite behaved as pure titanic acid. 



The forms of the substance are the same as those of Brookite, al- 

 though the planes are somewhat different. [T. R. J.] 



* Silliman's American Journal, New Ser. vol. ii. p. 249 ; and vol. iv. p. 279. 

 f [Dr. Shepard gives 3*854 as the spec. grav. — Ed.] 



