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channel a very thick incrustation of the same mineral, 
extending to some distance from the spring * A mineral 
spring at Carlsbad, depositing a mass resembling manganite, 
has been described by Kersten. Braconnet examined and 
described in 1821 f a precipitate of oxide of manganese 
found in the outlets of the springs of Lnxeuil. A deposit of 
the same mineral from the water in a mine at Freiberg has 
been analysed by Kersten and described in the “Archives 
fiir Mineralogie, &c.” (Vol. 16), and in this journal, also, 
Nogerrath has given an account of the nature and occurrence 
of the manganese ores in the Hundsruck, and in Soonwald, 
on the left bank of the Rhine. 
VI . — Associated Minerals. 
The most important minerals associated with the oxide of 
manganese in the strata of Ratcliffe Wood, besides the 
phosphate of alumina already mentioned, are brown iron ore, 
calc spar, pearl spar, iron pyrites, and zinc blende. The 
brown iron ore occurs in thin incrustations, in fibrous 
stalactitic masses, and in hollow spheres which have, 
especially on the inner side, a very peculiar lustre. The 
calcite occurs in a crystalline state in small fissures in 
almost every section, and is found crystallized occasionally 
in the form — JR. and the combination — J R. 16R. The 
pearl spar occurs in many fissures beautifully crystallized 
in the form — JR; it is tinged with oxide of iron, and the 
crystal faces are bent in the characteristic manner. Iron 
pyrites occurs abundantly, often perfectly crystallized ; and 
zinc blende is found in small masses scattered among the 
crystals of calcite and pearl spar. 
VII. — Conclusion. 
Oxide of manganese occurs in many places in the other 
Yoredale strata of the district, but nearly always in very 
small quantities. It also occurs widely spread throughout 
the overlying Millstone Grits; in these strata it forms 
# L’Institut, 1844. f Ann. de Chim. et de Phys., 1821. 
