326 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
trenched below the surface of this filling. A hundred acres or more 
of the surface of the northern portion of this plain consists of such 
loose gravel that there is not sufficient water retained at the surface 
to support any noticeable vegetation except mats of the lichen, Cladonia 
rangijerina, and a few trailing blackberry bushes. This deposit is 
near the head of what must have been a glacial sand-plain, for no 
other source of such material seems possible. At Hyde Park, 3 miles 
down the river from Morrisville, the plains above the river are at this 
altitude (660 feet). In fact, the upper terrace level for the next 15 
miles down stream, as observed in several places, is about 650 feet 
above the sea. The one farthest west is on the south side of the river 
at Jeffersonville. An eastern spur of this terrace is separated from 
the adjacent hill slopes by a depression which is strewn with angular 
boulders. The ice must therefore have been present in the depression 
while the terrace was forming. 
This terrace level, reaching from Morrisville to Jeffersonville, could 
not have been made before the Coveville stage of Lake Vermont for 
this stage of the lake attained an altitude of 650 feet at Jeffersonville. 
‘That much of the material of the terraces was deposited directly from 
the ice in deep water is shown by irregular cross-bedding in cuts near 
Jeffersonville and near the railroad station at Johnson, and also by 
regularly south-dipping gravel beds midway between Hyde Park and 
Johnson. The presence of ice during the deposition makes it proba- 
ble that several lakes at approximately the same level occupied the 
valley, discharging from one to another westward, through broad 
channels, rather than that a single body of water extended the entire 
length of the part of the valley in which the terrace was observed. 
A terrace at the 620-foot level, having much the same origin as the 
one at the 650-foot level, extends interruptedly from Hyde Park to 
Jeffersonville. At this level, the spur of the terrace at Jeffersonville, 
mentioned in the preceding paragraph, is covered to a depth of 
nearly 2 feet with a concentration of pebbles, a large part of which 
are from 1 to 4 inches in diameter. The valley here, at the time of 
this terracing, seems to have been free enough of ice to permit con- 
siderable wave-cutting on this spur. 
For the 8 miles next west from Jeffersonville the Lamoille valley 
is floored with water-laid materials which are dune covered in many 
places. Terraces at observed elevations of 535 to 550 feet, and 485 
to 500 feet were seen on both sides of the valley. Numerous sections 
indicate that, at least locally, lacustrine and fluviatile conditions have 
alternated more than once since the filling of the valley began. 
