334 ^^^^ American Geologut. J""^- ^^°^- 
ner how rapidly the material of these beaches is moving. In 
order to test the rapidity of this movement, I selected from the 
beach two pebbles which were striking- enough to be easily dis- 
tinguished from the others. One of these pebbles was spher- 
ical in form, the other had a roughly triangular outline with 
two flattened faces. The first of these, (weighing half an 
ounce), was throv.'n into the zone of wave action at a time 
when the waves were breaking at an average hight of six 
inches and at an angle of fifty degrees with the shore. It im- 
mediately began to move in a zigzag course along the beach, 
now washed diagonally upward upon the beach, now rolling 
backward with the returning wave. The two motions thus de- 
scribed were at an angle with each other and the apex of thi.^ 
angle pointed shoreward. Frequently the along-shore shove 
resulting from these two motions was as much as two feet, 
though its general average was sixteen inches. At one time 
this pebble moved three yards in nine minutes, at other times, 
however, the specimen became buried by the rolling mass of 
pebbles and it would be some time before the waves would un- 
cover it and start it along again. The larger of the two speci- 
mens weighed seven ounces and this when the waves were 
breaking at a hight of twelve inches, gave as a result of three 
trials, a linear motion of sixteen yards in ten minutes. With 
stronger winds, observations were impossible for the waves 
then became so muddy that one could not follow the move- 
ments of the specimen. 
At the entrance to '"The Pond" (see map), there is a 
curious hook on the end of the eastern beach, which is kept 
from growing across this entrance by the outflow of the land 
drainage and also by the piling up of the water in "The Pond" 
during stormy weather. During a strong on-shore wind the 
water backs up into this bay until the level of the water in 
"The Pond" is higher than that of the lake. A\'hen the wind 
subsides the water runs toward the lake again with a consid- 
erable current. This current, however, is not able to carry 
back the materials washed in bv the more powerful waves. 
Here again the waves are the most important factor and the 
current, though stronger than most currents in the lake, is ca- 
pable of moving little else than sand and clay. 
