196 ft. Pumpelly—Paragenesis of Copper 
The cavities in this variety are often less regularly defined in 
shape than in the brown amygdaloid. The enclosed mine 
are quartz, epidote, calcite, delessite, prehnite, laamonite, green- 
earth, analcite, native copper, orthoclase. These two varieties of 
amygdaloids often occur together without any well defined 
lines of separation, the bed being made up of irregular masses 
of the two rocks. In places, however, the brown amygdaloid 
forms a band one to two feet thick on the hanging wall, with a 
rather abrupt transition into the green amygdaloid underlying 
it; I have never observed the reverse. 
ple e “Ancient pit” bed on the | 
Shelden and Columbian property. | 
Conglomerates. 
The conglomerates of Portage Lake differ from each other 7 
but little, if at all, in lithological characteristics. The pebbles 
to minutely crystalline matrix, in which lie crystals, $-3 ™° 
long, of a flesh-colored triclinic feldspar. 
In some beds there appear pebbles of a flesh-red rock, com 
posed almost entirely of granular feldspar, containing small 
specks of a black undetermined mineral. In some instance’ 
the feldspar is wholly triclinic, in others the twin-striation ® 
aac aan absent. is variety of pebble is altogether absett 
in some beds, at least where they are opened, while in othe® 
ae ‘ “gor manent as in — ——. = — Conglomerate 
ebbles compact melaphyr and of melaphyr amygdaao" 
also occur, | ronueae cubeidinate in saieaber ethos already 
