On the Paragenetic Relations of Minerals. 61 
panied only by quartz at two places, near Schneeberg, at 
Steinig (Voigtland), and likewise in iron and manganese 
lodes in some mines at Johanngrogenstadt, generally upon 
red jasper. Chalcolite occurs in the same lodes on quartz 
or red jasper. The circumstances of their occurrence render 
it probable that the granite on both sides of such Jodes con- 
tains a uraniferous mineral, disseminated so finely that it has 
not yet been recognised. Such uraniferous minerals have 
been found imbedded in granite, as at Redruth in Cornwall. 
The beraunite, kraunite, kakoxene, &c., in lodes of slight 
depth in Bohemia, have perhaps likewise derived their phos- 
phoric acid from the surface. 
Pyromorphite and the phosphates of copper belong here as 
the most recent products of the decomposition of cupreous 
minerals, and the arseniates of copper generally contain some 
phosphoric acid. ‘These are thus proved to have been de- 
rived from above. 
Childrenite, belonging to the same genus as skorodite, is 
likewise recent. 
Vivianite occurs upon quartz, spathic iron, and iron pyrites, 
in Wheal Betsy, Tavistock, Wheal Kind in Cornwall, and 
in Hungary. In Bavaria, thraulite occurs between them. 
Wavellite occurs alone or with peganite and anhyposiderite. 
To these may perhaps be added pleurokens, triphylin, hete- 
pozite, triplite, zweiselite, and lazulite. It is not said that 
these all belong to the same formation, so much as that they 
are the most recent minerals in lodes, and are never found 
at any depth. Apatite, allogonite, amblygonite, are certainly 
to be excepted, together with some others. 
General Results —The true anhydrous silicates occur, for 
the most part, as constituents of rocks, less frequently in 
lodes. In the latter case they indicate a very great age; 
garnets, felsites, amphiboles, pyroxenes, &c.; but some few 
silicates occur either chiefly or only in lodes and ‘‘kalkstécken,” 
é.g., Skapolite, epidote, zygodite, &c. Hydrated silicates occur 
almost only in lodes and vesicular cavities. Quartz, calcite, 
(including limestones) and dolomite, are not only important 
constituents of many rocks, but are uncommonly frequent in 
lodes as well as many other members of the spar group, 
