1852.] 



109 



The constituents of Karpholite, by two analyses one by Stromeyer and one 

 by Steinman, as recorded in Dana's Mineralogy, are : 



Si Silica 

 ... 



Al Alumina . 







Mn Oxide of Manganese 

 Fe " Iron 



H Water 



10-78 



11-86 



HF Hydrofluoric acid . . 1-47 



Karpholite is therefore essentially a hydrated silicate of alumina and manga- 

 nese, and entirely different in its composition from the mineral in question. 



Before the blowpipe this mineral fuses readily, and a sublimate is formed, 

 which, if the mineral is supported on its quartz matrix, forms a bluish ring on 

 the quartz ; and a brilliant yellow color is imparted to the flame. With mic. 

 salt, in the interior flame, it forms a green bead. 



In its easy fusibility and in the production of this curious bluish ring, con- 

 densed on the quartz around the fragment exposed to the blowpipe flame, this 

 mineral is readily distinguished by the blowpipe from Karpholite, which fuses 

 with difficulty, and forms no such ring. 



In the works on mineralogy, there is a meagre notice given of an ore of molyb- 

 denum, under the name of molybdic ochre or oxide of molybdenum, which occurs 

 in powdery incrustations of various shades of yellow, and is in fact molybdic acid, 



being composed of molybdenum 63-66, and oxygen 33-39 (Mo.); but as this 

 mineral contains no iron, is produced from the decomposition of the sulphuret of 

 molybdenum, and has never been found in the fine delicate tufted acicular crys- 

 talline form, it is probably not the same as this California mineral. 



I have not yet had a sufficient supply of the ore to ascertain the proportion of 

 oxygen united with the molybdenum in this mineral, but I am led to believe 

 that it exists in the state of molybdic acid, from the fact of ammonia acting on 

 it so readily. I think, moreover, that the molybdic acid is combined with the 

 iron, for the pure rich yellow color of the mineral forbids the idea of the iron 

 being only mechanically mixed ; and besides the iron is very nearly in the pro- 

 portion to form a subsalt : hence I infer that this mineral must be a submolybdate 

 of iron. 



Ji'lOLl. 



The Committee to which was referred the following by Mr. Lea, 

 reported in favor of publication in the Proceedings : 



Description of a new species of Eschara^from the Eocene of Alabama. 



By Isaac Lea. 



Many years since I received from the late Judge Tait of Claiborne, a large 

 number of fossils from the Eocene 

 beds of that district, and among 

 the sand was found a fragment of 

 this interesting genus. I did not 

 then characterise it, in the hope of 

 getting a more perfect specimen. 

 I have not, however, seen any 

 other but this fragment. 



There have been a number of spe- 

 cies described by Mr. Lonsdale, in 

 the Journal of the Geological Socie- 

 ty, vol. i., from the Tertiary of the 

 IT. S. These were taken by SirC. 

 Lyell to London, on his return from 

 one of his tours to this country. 

 The species which I propose to 

 characterise, differs in its form 



