314 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
of the Green Mountains was nearly free from ice. Taylor (1903, 
p- 363) finds evidence in the Berkshire Hills that the Green Moun- 
tains were an effective barrier to the eastward extension of the ice- 
front during its retreat from western Massachusetts. For a long 
time after the main portion of the ice-front began to be confined to the 
western side of the Green Mountains there were still remnant tongues 
pushing eastward through the gorges of the Winooski and Lamoille 
rivers. In the Winooski gorge, near Bolton, roches moutonnées 
with the plucked sides on the east give conclusive evidence of such 
movement.’ ‘The effects of these tongues of ice in the gorges upon 
the drainage of the valleys east of the Green Mountains will be con- 
sidered in succeeding paragraphs. 
SHORE-LINES IN THE CHAMPLAIN LOWLAND.— It is convenient 
to begin with the southernmost shore-line features to be considered, 
and proceed northward. The location of the places mentioned may 
be found on the map, Plate 2. 
Bristol to the Winooski Delta. The Middlebury sheet shows the 
village of Bristol to be situated on a terrace 600 feet in elevation. A 
mile west of the village, north of the railroad crossing, there is another 
terrace at the altitude of 490 feet. From the description which C. H. 
Hitchcock (61, vol. 1, p. 131) gives of the surface of these terraces 
and from their topographic relations, I am led to classify them as 
deltas and shore-cliffs, and to correlate them with the two highest 
stages of Lake Vermont, namely: — the Upper Coveville and the 
Coveville. 
Beginning at Bristol and extending north to Hollow Brook, on the 
east side of the Hogback Mts. there is a longitudinal valley part of 
which drains northward by Lewis Creek, and part southward by Bea- 
ver Brook. The south-draining part of the valley was evenly graded 
by a filling of water-laid deposits, and was afterward trenched by 
stream erosion.? It is from this valley that the Bristol delta extends. 
The large amount of water-laid materials in the valley, and the size 
of the Bristol delta make it evident that no small amount of drainage 
from the ice coursed through the valley while the delta was building 
into Lake Vermont. The altitude of the valley deposits makes it 
seem probable that the process of valley filling began during the latter 
part of the existence of Lake Albany. 
1T have not noticed any evidences of local glaciation in northern Vermont. Chalmers 
(98, p. 28) and Upham (95, p. 18) are of the opinion that considerable bodies of ice 
remained in and east of the Green Mts. after the Champlain valley was free of ice. 
2 It is from the U. $. topographic maps, and the descriptions in Hitehcock's report 
(61, vol. 1, p. 131, 141) that I get the facts concerning the deposits from Bristol to 
Hollow Brook. 
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