326 
MANGANESE DEPOSITS OF INDIA : GEOLOGY. [PaRT 11 : 
sufficient quantity for the need for such a term to be felt. The nearest 
rock to gondite seems at first sight, on account of the spessartite 
present, to be that to which the name queluzite has been given by Dr. 
Or%alle Derby; but, as will be judged from page 27i, this rock is 
really considerably different to gondite, and more closely related 
to kodurite, one of the chief points being that it is supposed to be of 
igneous origin. To varieties of the spessartite- quartz-rocks of coarser 
grain the name gondite may also be extended, but such rock is not to be 
regarded as the typical rock. Under this extended meaning of the term 
some varieties of gondite will possess quite a coarse-grained structure, 
the garnets sometimes being as large as an inch in diameter. Very 
often the manganese-silicate rock consists entirely of garnet, the quartz 
being absent. It will then be known as spessartite-rock. When the rock 
contains important quantities of apatite, as at Jothvad in Narukot, 
the rock is an apatife-gondite. Spessartite-quartz-rock containing 
rhodonite is rhodonite-gondite. It is not proposed to introduce any 
special name for the rocks rich in rhodonite, because rhodonite is a much 
less common mineral than spessartite in the rocks of this series. 
The rock found at many localities, composed entirely of rhodonite, will 
therefore be known as rhodonite-rock. There may be a small quantity 
of manganese -garnet present, which may increase in quantity until it 
predominates over the rhodonite. The rock then becomes rhodonite- 
spessartite-rock or rhodonite-gondite, according as quartz is absent or 
present. Sometimes the rock contains a brownish to greyish radiate 
fibrous mineral that is probably an amphibole. Such a rock would be 
termed an amphihole-gondite. Occasionally scales of a manganiferous 
mica may be present in the spessartite-quartz-rock. The rock is then a 
mica-gondite. The other rarer rocks found in this series, such as the 
garnet-rhodonite rock containing bar}i;es and a manganesian phosphate, 
fovmd at Chargaon, Nagpur district, will be known by the names of 
their constituents. There are many other varieties of rocks in this 
series ; but it is not necessary to explain the meaning of their names as 
given in the complete list on page 329 ; they are self-evident after the 
foregoing explanation. 
Before proceeding to give a brief account of the petrology of the rocks 
. f,i, u J- of the gondite series, it win be necessary to give a 
Structure of the bodies » j-n rii T r 
of manganese-bearing short account of the structure of the bodies of ore 
and manganese-bearing rocks. Except when the 
ore-bodies are composed entirely, or practically so, of manganese-ore, they 
usually exhibit a banded structure due to the alternation of layers of 
