10 GEOLOGICAL MEMOIRS. 



Finally, the Silurian Formation of Bohemia has supphed 42 

 additional species of Crustacea, 37 Pteropoda, 285 Cephalopoda, 

 altogether 364 species, the description of which will be given in 

 my Second Volume. [T. R. J.] 



PsEUDOMORPHS. By A. Breithaupt. 



[Hartmann's Berg- u. Huttenmiinu. Zeit. 1853, pp. 401, 402, 404. Leonhard u. 

 Bronn's N. Jahrb. f. Min. u. s. w. 1853, pp. 837 & 843; and 1854, p. 76.] 



Native Silver and Silver-glance for Red-Silver-Ore. — The combina- 

 tion ^R with R 00, in which the prism is much lengthened, Aery fre- 

 quently observed in red-silver-ore, has been pretty certainly found in 

 the purest native silver, in the Sauschwart mine, at Sphneeberg. The 

 crystals are hollow, with the prismatic walls sometimes broken 

 through. Diminution of the space occupied is here very observable. 

 The author has also seen the peculiar form of red-silver-ore in the 

 silver-glance of Schneeberg : the mine is unknown. 



Copper-pxjrit es for Nadel-erz. — At Lohna, near Schleiz, in the 

 Principality of Reuss-Schleiz, copper and silver mines have been 

 worked to a considerable extent at some early period, but all records 

 are lost. In the grey horustone and hard grauwacke there occur nadel- 

 erz [plunibo-cupriferous sulphuret of bismuth, = patrinitej, fahlerz 

 [grey copper], and copper-pyrites ; and in the clefts, kupfer-lasur 

 [blue carbonate of copper, = chessylite] and malachite ; and there are 

 also solid masses of anthracite. The nadelerz has altogether the 

 appearance of that from Beresoifsk, Siberia, and, according to Plattner's 

 blow-pipe researches iu its composition, it yields a very little iron and 

 2 to 2| ounces of silver in a hundredweight [English] . The acicular 

 crystals consist partly of nadelerz, and partly of this and copper-py- 

 rites, — most, of copper-pyrites, with a distinct and very considerable 

 diminution of the space occupied : iu this respect, similar to what we 

 see in the tourmaline and the mica that takes place in the granite of 

 Kursdorf, near Penig, iu Saxony. 



Iron-pyrites, Red ochre, and Acicular Iron-ore for Banjtes. — Xt 

 Przibram in Bohemia some very interesting pseudomoi'phs have lately 

 been found, occupying the place of barytes and indeed of its combi- 

 nation oP ; P (X I P 00 with and without x P, the impressions of 



which in the cavities are quite sharp. First of all there is a thick 

 coating of iron-pyrites ; on that, a very thin one of red ochre [Roth- 

 eisenerz] ; and lastly, a thin coating of velvetty acicular iron-ore 

 [Nadel-eisenerz], On the last there is a calc-spar in rhombohedrons 

 — ^R, but only in very small isolated crystals. 



Picrophyllite and Green-earth for Augite. — Breithaupt saw Picro- 

 phyllite iu the form of augite ; it is nothing more than decomposed 

 augite. Green-earth for augite occurs iu the melaphyre of the Fassa 

 Thai, Tvrol, and at Tekoro in the Siebenbiirge, in the same rock 



[T- K- JO 



