GoLpTHWAIT. — Sand Plains. 
PLATE 38. 
Tilted water-planes of Lake Sudbury. The significance of this diagram may best 
be seen by superposing it on Plate 4, to which it is supplementary. It shows 
how the same points, plotted as in Plate 4, might less perfectly be grouped into 
a series of more steeply tilted planes, which slant about 13 feet to the mile. 
(See page 295.) 
PLATE 4. 
Tilted water-planes of Lake Sudbury. The altitudes of lobes and outlets, given on 
the map (Plate 5), are plotted in profile, with reference to a north-south line. 
The points fall close to a series of planes which rise northward at the rate of 
about 7 feet to the mile. The horizontal scale is the same as in Plate 5; ver- 
tical exaggeration about 75. 
