SMUGGLER MOUNTAIN. 189 
limestone which forms the base of the Maroon. Near the contact of the 
gray Maroon limestone with the Weber shales there is a heavy breccia, 40 
or 50 feet thick, which shows movement, probably along a bedding fault. 
Near this fault zone the shales are bent from their normal position. After 
passing through a considerable thickness of shale some porphyry is tray- 
ersed, and then shales to the contact with the brown Leadville dolomite, 
where the Silver fault comes in. There is no blue limestone in the tunnel, 
or indeed anywhere in the Smuggler Mountain mines. After cutting 
through the Leadville dolomite a little distance the Della fault is encoun- 
tered, as a consequence of which the Parting Quartzite crosses the tunnel. 
Passing through the fault, the tunnel swings to the north until it again 
reaches the Silver fault, and from this point runs in a general northeasterly 
direction, in Leadville dolomite, not far from the Silver fault. Sometimes, 
however, it gradually diverges a considerable distance from the fault, as is 
the case opposite the Park Regent station, where the Parting Quartzite 
outcrops in the tunnel. The strike of this quartzite is nearly parallel with 
the trend of the tunnel, but is a little more easterly, so that it enters the 
tunnel from the south and passes out of it when the tunnel begins to curve 
to the north, as it does at this point. The curve in the tunnel was necegsi- 
tated by the action of a small east-west fault, which is called the Regent. 
This has shoved the formations to the west on the north side. From this 
point the tunnel runs entirely in dolomite until in the Alta Argent mine 
another east-west fault is encountered, which has likewise a movement to 
the west on the north side. Just before reaching this fault the tunnel had 
again run so deeply into the Leadville dolomite that it is nearly down to 
the Parting Quartzite, so that on crossing the fault it runs into Silurian 
dolomite, the Parting Quartzite having been shoved over to the west side, 
where it probably soon runs into the Silver fault. 
The Smuggler Mountain mines which this tunnel connects form a 
continuous series of workings reaching from the Smuggler on the south 
to the Alta Argent on the north. 
DELLA S. MINE. 
The Silver fault has been followed throughout the Della S. as the 
horizon on which ore most usually occurs. On the west side of this 
fault is the Weber shale, and on the east the Leadville dolomite, with no 
