pee 
Scheerer on Isomorphism. 389 
spection of the localities in question, that it will ever be met with. 
ot any where in the Snarum serpentine, is there any indication 
of that weathering or other decomposition of the rock, univer- 
sally observed as accompanying such pseudomorphs as are here 
treated of. The crystals of serpentine, in themselves perfectly 
fresh and colored green by silicate of the protoxyd of iron, are 
either imbedded in magnesite not less fresh and showing brilliant 
anes of cleavage,* or else they occur in perfectly undecomposed 
titaniferous iron. Now and then upon breaking up the latter, por- 
tions of serpentine are met with imbedded therein. There are 
not met with here either clefts, cracks, or drusy cavities, indica- 
tive of any infiltration, formation of veins, or any thing of that 
kind ; but serpentine, magnesite, titaniferous iron, mica, and some 
few other minerals met with here, occur closely and intimately 
mixed up together, forming a ribbon-shaped zone in the primitive 
gneiss, as has been demonstrated by Bébert in his article “ Upon 
the Serpentine Formation in the primitive district of Modum.”’+ 
_ There are met with, it is true, at this locality, erystals of serpen- 
tine more or less weathered, in which case, owing to the protoxyd 
of iron being raised to the peroxyd, they are of a dirty yellow or 
brownish color, and indeed most of the specimens preserved in 
collections present that appearance ; the reason thereof is simple 
(To be continued.) 
nee ee 
This was formerl d b bi r- See Po, . Ann. yol, Ixy . 292. 
y suppose to be bitte spar. 2s . 2p 
f See Gaa Norvegica, part i, p- 127. 
