IS94-] 207 [Woodworth. 
represents the coarse of this esker from near Lasell seminai-y 
in Auburndale to its junction with the sand-phain about one 
mile south. The Une C D represents in vertical ])rojection upon 
the same plane the variations in elevation of crest-line for corre- 
sponding points of the line AB. The line E F may be taken in 
liorizontal ])rojection to give the average course of the esker; in 
vertical projection, to establish the base of comparison for the 
crest-line C D. These two lines thus drawn, showing the 
course and the elevation of the esker at each moment, may be 
said to give the Uries of the esker. 
Mr. Geo. H. Barton informs mo that he finds a similar corre- 
spondence in the lines of the esker north of the Charles River, 
in apparently the same drainage line as the segment at Auburn - 
dale. Mr. F. C. Schrader, a graduate student in Harvard 
University, has prepared a manuscript map of the short esker 
between East Watertown station and the U. S. Arsenal, in 
Watertown, Mass. This esker terminates southwardly in a sand- 
plain. Near its junction, on the east side, is a spur or kame, 
probably marking the site of an alcove in the ice. The most 
interesting feature of the ridge is its passage by a small brook. 
Mr, Schrader found that the notch has been made where the 
course of the esker changes from S. 5° W. to S. 40° W, The 
esker also exhibits tlie commonly observed depressed crest-line 
near its confluence with the sand-plain. At the point where 
the crest-line falls off in elevation, the dii'ection changes from S. 
40° to 55° W., to S. 15° W. This esker is then a small example 
with accordant lines. The average course of this short ridge 
is S. 24° W. 
Since formulating this graphic method of expressing the 
topographic features of eskers, I have not been able to a])ply it 
extensively to eskers in the field. It is true that many eskers do 
not display a consistent and regular variation in their lines. 
With this view in mind, my friend, Prof. W. H. C. Pynchon, 
now of Trinity College, examined the esker lying in the densely 
thicketed tract east of Randolph in the town of Canton, Mass. 
He found that the crest-line varied in height where the course 
changed, but there were numerous other variations not clearly 
coinciding with meanders. 
In the case of the Auburndale esker it seems possible to draw 
inferences from its lines. Its meanders indicate a zigzag 
