44 The American Geologist. Julv 
to find below Leavenworth mountain any evidence of glacia- 
tion. The mountain slopes are here wholly unglaciated, and 
all apparent moraines are really detrital cones heading in later- 
al gulches, forcing the creek against the base of the opposite 
slope and thus causing it to meander in spite of its rapid fall. 
But even granting that the glacier of the Clear Creek valley 
did cross the site of Georgetown, the salient northwestern 
angle or spur of Leavenworth mountain would prove a still 
more serious obstruction than before ; nor could we appeal with 
more success to the phenomena of the bergschrund, for surely 
this basin, a dozen miles from the heads of the valleys in the 
Snowy Range, was never an amphitheatre of neve ; on the con- 
trary, we must think of it as in any case near the lower limit of 
glaciation and well below the line above which the formation 
of glacial ice or its firm adhesion to the bounding rocks' is pos- 
sible. 
We have next, then, to inquire whether the facts are more 
favorable to the displacement hypothesis. In this connection 
some of the vein phenomena of the district are significant. Tra- 
versing the lower slope of Griffith mountain, to the north of 
Leavenworth creek, is the Griffith lode, which may be regarded 
as virtually continuous to the south and southwest with the 
lode system of the Alaska, Centennial, Burrell, and Big Indian 
mines, crossing the mouth of Leavenworth gulch just below the 
escarpment and traversing the northern face of Leavenworth 
mountain to and through the prominent notch high up on its 
northwestern spur. The workings of the Centennial mine with 
a depth of 600 feet and a length of over 1,500 feet, extend di- 
rectly across the mouth of Leavenworth gulch and reveal per- 
fectly the character of the fissure at this most critical point. 
Here, as throughout its course, it is an approximately plane, 
vertical, and vertically striated wall, characterized at most 
points by a clay gouge from six inches to a foot or more in 
thickness, and by more or less extensive sheeting of the granite 
complex, as well as by frequent oblique breaks, or branch fis- 
sures, in which the filling of quartz and ore chiefly occurs. A 
more ideal fault fissure it would be difficult to imagine ; and 
that the movement has been in part geologically recent is in- 
dicated by certain features of the Griffith and neighboring 
mines to which my attention has been directed by .Mr. J. S. 
