46 TACONIC PHYSIOGRAPHY. 
end of the Taconic Range and 4 miles north of the northern edge 
the area mapped is the fault scarp of Snake Mountain, in Addis 
Comity, Vt. The cliff faces west and is nearly 1,000 feet higher tl 
the surrounding portion of the Lake Champlain Valley. This fa 
scarp is the first conspicuous topographic feature norfh of the Taco 
Range. The southern end of this fault appears at the northern ec 
of mapped area. 
The two longer quartzite inliers in Shoreham, Vt., are fault 
monoclines, whatever scarps may have formed their western sic 
ha vino- been eroded. 
TALUS SLOPES. 
The action of frost on the much-jointed quartzite cliffs of Moil 
ment Mountain has probably formed the talus shown on each side 
the mountain (fig. 2 and p. 45). To this additions are made year 
year. Wherever the quartzite of the western flank of the Green Mov 
tain Range is exposed a talus has likewise been formed, the size 
which depends upon the position and magnitude of the outcrop a 
the character of the primary and secondary structure. A very lai 
talus of blocks up to 20 feet in diameter occurs at the foot of Wh 
Rocks, in T\ allingford, Vt., 5J miles east of Tinmouth village a 
beyond the edge of the mapped area. (See Pis. II and XII, A, I: 
The gentle western slope of the range in places may be due to a simil 
talus mantled by vegetation. Another but much smaller talus 
large blocks occurs on the same range north of the Bear Spring 
Williamstown. Here longitudinal and transverse joints and mini 
folds with cleavage planes furnished the requisite structural cone 
tions. On the western side of Mount Moosalamoo, which rises to ; 
altitude of 2,088 feet above Lake Dunmore (PI. XIII), there is ; 
extensive quartzite talus masked by forest. Some of the blocks a 
over 40 feet in diameter. The origin of this talus may be associat 
with the fault which occurs on the cliffs above it. Indeed, the stru 
tural relations of the Silver Lake syncline and Mount Moosalain 
seem to require a transverse or diagonal fault there. There is a gi 
talus at Slide Mountain on the northwest corner of the Renssela 1 
Plateau, in Pittstown, X. Y. An extensive talus of schist, exposed 
few years ago by a forest fire, occurs a short distance east of tl 
top of Mount Greylock and 800 feet below it. A pronounced cleavar 
foliation, dipping steeply to the east, crossed by vertical east-we 
jointing and a low westerly dipping stratification, afforded favorab 
conditions, and the erosive power was supplied either by frost or tl 
motion of the glacier diagonally across the summit. The recei 
landslide has finely exposed this steep east face. 
