ology and Mineralogy- !'-*> 



graphs of the specimens and too indistinct t<> form a judgment 

 from. The author seems to have thoroughly ransacked the lit 

 eratnre of the subject and his " Elenco Cronologico " which forms 



the second part is a very full list of papers relating in any way to 



the fossil botany of Italy, considerably fuller than that of I'ortis. 

 It embraces 262 titl< l. p. w. 



L6. Jarosite from Utah ; by V. A. Gbnth. (Communicated). 

 — Messrs. Geo. I.. English & Co. have recently brought from the 



.Mammoth .Mine, Tintic District, Utah, interesting varieties of 

 Jarositi in minute crystals, lining cavities of a siliceous limonite, 

 and sometimes associated with a pulverulent, yellow mineral, 

 probably a l>a<ic ferric sulphate. The crystals are of a yellow- 

 ish brown to dark clove-brown color and a very brilliant vitreous 

 luster; they are very small, from about O'l to l" 1 " 1 in size, and 

 look so much like cubes with tetrahedral planes, that they were 

 mistaken tor pharmacosiderite. A closer inspection, however, 

 showed their rhoinbohedr.il forms. Prof. Samuel L, Penfield had 

 the kindness to examine them for me, and gives the following 

 information. "The crystals are so rounded that they will not 

 give distinct and satisfactory reflections. From a very small crys- 

 tal I obtained R^R ^° l'V, while Naumann gives 88° 58' for 

 jarosite, an agreement as close as I could expect. I also identi- 

 fied the base, and a very small plane — 2R. I was able to pro- 

 duce basal cleavage." 



Even the best specimens placed in my hands by Messrs. Eng- 

 lish & Co. did not furnish me with absolutely pure material for 

 analysis, owing to the fact that the crusts are very thin and the 

 crystals stick so fast to the siliceous matrix and often enclose the 

 latter that only at the expense of a great deal of time and patience, 

 about one gram of nearly pure fragments of crystals could be ob- 

 tained (I) ; analysis (II) was made with somewhat larger and darker 

 crystals. Both show a slight contamination with siliceous limonite 

 — but the analyses leave no doubt that the mineral is jarosite. 

 Spec. grav. of I (taken in alcohol) = 3-163. The analyses gave : 



i. ii. 

 008 0-29 



Feo0 3 50-41 51.16 



Na,0 \ Q .,,„ 033 



K 2 $ 9-05 



29.60 28.93 



H 2 1068 10-21 



Chem. Laboratory, 111 S. 10th St., Philadelphia, October 13, 1889. 



17. Brief notices of some recently described Minerals. — Red- 

 ingtonite, Kxoxvillite. Two hydrous chromium sulphates 

 from the Redington mine, Knoxville district, California. They 

 occur at a depth of 150 feet at a point where solfataric gases still 

 issue and are regarded as the result of the solfataric action upon 

 chromic iron. Kcdingtonite occurs in masses with a fine fibrous 

 structure and of a pale purple color; the extinction is oblique 

 (13° to 38°) and a triclinic form is suggested. A qualitative 

 5* 



