260 ms | 
by the occurrence upon the highest level of a sharp kettle hole 300 feet in 
diameter and 25 feet deep, marking the place where a detached ice block 
stranded and melted. 
The occurrence of kettle holes in deltas is not uncommon.t A remark- 
able case of this kind has been described by the writer where an area of 
ten acres of delta surface is thickly pitted with small kettles. (Fig. 4.) 
This delta is the joint product of a land stream and a valley glacier which 
contributed ice blocks and an undetermined portion of the permanent ma- 
terial. There are probably many intermediate forms between such a 
morainal delta and one due whelly to stream work. 
ichcoe or 
RTL WL 
Fig.5. Outer Face of Morainal Delta. Fan in front of notch. 
When lake waters are withdrawn the bisection of a delta may result in 
the formation of an alluvial fan in front of it. This gives a characteristic 
combination of notched delta and fan. (ig. 5). The fan of Mill Creek at 
the foot of Honeoye Lake is a mile in diameter, and is responsible for the 
existence of the lake, to which it acts as a dam. The fan of Canadice out- 
let bears a similar relation to Hemlock Lake, which, however, is too deep 
to owe its existence wholly to that cause. 
Deltas occasionally take the form of long, narrow ridges upon one or 
both sides of a stream, resembling the natural levees in “the goosefoot”’ 
‘Fairchild, Journal of Geology, Vol. 6, p. 589. 
? Bulletin Geological Society of America, Vol. 15, p. 457. 
