REPORT OF THE DIRECTOR, 1922 145 
Vermiculite. Associated with the clay or kaolin is one of the 
altered micas, presumably vermiculite, a mineral of yellowish 
gray color and pearly luster and exhibiting strong exfoliating 
characteristics. This mineral might very well have been derived 
from phlogopite or scapolite so common in the country rock and 
in all likelihood a constituent of the original brecciated zone. 
Asphalt. The most unusual mineral association occurring in 
this vein is that of asphalt which is found as brilliant jet black 
substance coating some of the other mineral contents of the 
boxes, particularly quartz. It hardly occurs in sufficient quanti- 
ties for chemical examination but sufficient for blow-pipe tests 
when it showed a cokelike substance after fusing. Which variety 
of asphalt this is can only be determined after a thorough chemi- 
cal examination upon more material but what preliminary solu- 
bility tests were made would place it either as albertite or gram- 
hite. 
It is also found as spherical inclusions in the quartz and some- 
times coating lumps of kaolin or clay within the other cellular 
structures. Whether it found its way down into the brecciated 
zone from the once overlying Ordovician calcareous formations 
through the agency of circulating silica-bearing waters or from 
more distant sources can not be answered at this time. The well 
known similar occurrence in the quartz crystals in the dolomite 
at Little Falls and Middleville described by the late Professor 
Cushing (7) may have some bearing on this problem. 
Manner of Formation of the Mineral Contents of the Boxes 
The filling of the banded and comb structures as well as the 
fracture planes forming the sides of the boxes can be accounted 
for by mineral-depositing solutions causing the formation of 
manganiferous calcite and quartz either as alternating bands or 
quartz filling for the comb and box structures, but the filling of 
the boxes is not so obvious. We find in some of these structures 
that there is a regular sequence of minerals beginning with the 
quartz followed by pink calcite and then by crystalline calcite 
with occasionally sphenoids of chalcopyrite. On other walls, 
only inward pointing quartz crystals are found with occasional 
crystals of calcite on the quartz. We have evidence that some 
of the mineral contents of these structures are the residual prod- 
ucts of the originally fractured or sheared limestone and their 
presence in the boxes can be accounted for by the solution 
