1884.] Mineralogy. 927 
the naked eye. They form a crust on compact quartzite. They 
occur in regular hexagonal prisms and have a micaceous basal 
cleavage. They are optically uniaxial, and belong, therefore, to 
the hexagonal system. : 
Jeated in a matrass, acid water is disengaged, and the mineral 
becomes red. In the blowpipe flame it fuses to a black scoria. It 
is attacked by chlorhydric acid heated to the boiling point, but 
not by nitric acid. 
Analysis gave (Damour) : 
O, AsO; FeO; H,O 
28.45 3.19 58.82 9.32 
Formula; 3Fe,0, 350; + 4H,0 
FLEXIBLE SANDSTONE.—In a note in the June NATURALIST on 
' flexible sandstone from Pennsylvania, its flexibility was regarde 
as due to its decomposition. As regards the itacolumite of 
Brazil, Mr. J. C. Branner, formerly of the Geological Survey of 
Brazil, writes to us as follows: 
so much leather, and only a few fragments would be broken off 
about the mouth of the hole. On account of this difficulty in 
ace. But in the deep gold mines in the itacolumite this 
flexibility was never found very far beneath the surface. ret 
to say that I made no exact measurement of the depths at which 
it ceases. I may say, however, that at a distance of about a hun- 
characteristic flexibility had disappeared entirely. ; 
‘Again at a certain stage of decomposition more advanced 
than that indicated by flexibility, this sandstone simply fell apart 
when broken in the hand, or could be cut through more easily 
of decomposition of itacolumite by noting the depth at which 
it ceases to be flexible.” 
Mineratocicar Notes.—A union has been effected between 
tiie Mineralogical Society and the Crystallogical Society of Great 
Britain, The Crystallogical Society brings with it several miner- 
alogists of high attainments, who will be likely to make the 
