60 
MANGANESE DEPOSITS OP INDIA : MINERALOGY. [ pART 1 : 
faces, two n faces, one x face, and one g face. The formula of the face g 
is completely determined as (201) by the fact that it is situated in 
the two zones whose symbols are [112] and [112]. The angular measure- 
ments confirm the symbol (201). 
For the Lohdongri crystals I am mainly dependent on the notes 
^ . I made when at Lohdongri, where Mr. E. L. Young 
tals. ^ '^^'^^^ '^'^^ has a fine set of specimens of braunite from this 
deposit. One of these, kindly lent to me by Mr. 
Young, is shown in Plate 2, from which it will be seen what a size the 
Indian braunite crystals sometimes attain. This specimen shows the 
simple octahedron or pyramid, p, one of which measures 3 inches along 
an edge between two pyramid faces ; one of the pyramids is truncated 
by c. Of some small crystals presented by Mr. W. H. Clark of Kamthi, 
three show the simple octahedron, whilst one is a contact twin on e, of 
the habit represented in fig. 1 , the forms present being p and x. Of the 
specimens I examined at Lohdongri, one is represented in fig. 10, being a 
combination of p and m, with the prism of the second order, a or (100), 
which I have not seen on any other Indian specimen. Another crystal 
showed a combination of c, p, x, and the rare face e or (101), which, 
although commonly found as a twinning plane, is very rarely seen as a face 
on braunite crystals. Other crystals show combinations of c, p, and y, 
similar to fig. 4, but with c and y more prominently developed relatively 
to p. One octahedron was elongated along a horizontal axis bisecting 
the angle between the two lateral axes of braunite, so that the trun- 
cating basal plane was drawn out into a long rectangular face. 
From Kodegaon only one crystal has been obtained. This is a 
, fine specimen, which if whole would be some 2 to 3 
The Kodegaon irys- . j. ■ r i. • v. 
tal. mches across. It is ol great interest on account 
of the faces shown, being a combination of p, y, 
and the rare form e, all well developed, with in addition a new form z. 
^ ^ This is a ditetragonal pyramid that is less steep than 
e, and consequently forms the top end of the crystal. 
Only two faces are shown, and on account of the large size of the specimen, 
so that it cannot be accurately measured on the reflecting goniometer, 
and the fact that the new face cannot be referred to two intersecting zones, 
or even to one zone with two known faces, I have not yet been able to 
determine for certain what is the symbol of the face. It may be 
either (425) or (849) ; the measurements agree more closely with (425) 
than with the other form. As this form has not yet been certainly 
determined I have not figured it here. 
