INGIPOI OP AMEN, IDINKIC WOR, OZ 143 
The exterior walls of these structures where adjacent to the car- 
bonate bands, consist of a granular crystalline aggregate repre- 
senting the truncated crystals which project inward to form the 
interior lining of the box or comb structures. But scattered 
through or above these grains, are small crystals whose c axes 
lie in the plane of these structures presenting a drusy appearance. 
On some of the plates, especially those that are a part of the 
banded structures, there is the drusy habit. As this mineral is 
not unusual in its physical characteristics nothing further need 
be said about it other than the fact that it rarely contains 
spherical inclusions of some black substance, presumably of an 
asphaltic nature. 
Manganiferous calcite. Special emphasis has been given to: 
this mineral because of the nature of its occurrence and its rela- 
tive age. As can be seen from a study of the deposit and the 
specimens it is almost if not quite as abundant as the quartz and 
in its occurrence observes a remarkable parallelism whether in 
the banded, comb or box structures. It is of a pinkish or brown- 
ish pink color, of medium grain and crystalline but without well- 
developed crystals. Good cleavage is seen in the banded struc- 
tures. Its ready response to cold hydrochloric acid makes it a 
variety of calcite rather of rhodochrosite. 
So far as its paragenesis is concerned, we find it of earlier age 
than the quartz, the latter cutting and including it repeatedly. 
This mineral is the first cementing and replacing one of which 
there is definite record. 
Calcite. In less abundance than the two foregoing minerals, 
calcite is found as crystalline aggregates of either anhedral or 
euhedral forms, associated with the quartz linings of the cellular 
structures. The crystals show normal rhombohedra (tofu), 
scalenohedra (2131) or modifications of both. In some of the 
boxes and other cellular structures there is a banding of minerals 
- inward from the quartz shell in which the following arrangement 
is observed: quartz, pink carbonate or manganiferous calcite 
and calcite. Calcite seems to have been of later age than the 
quartz and the manganiferous calcite. Incrusting some of the 
quartz crystals, is a coating of amorphous lime carbonate, not 
unlike calcareous tufa in habit, a deposit from lime-charged waters. 
Chalcopyrite. This mineral is found as isolated sphenoids or 
as penetration twins. The sphenoids are rarely and exceptionally 
large; one of them measures seven-eighths of an inch from the 
