12 The American (,'coloc^ist. juiy, 1901. 
other photograjjhs taken, of which two are reprochiced in fig- 
ures II and 12. The \ioor Hghting in tlie last two views does 
not ])roperly show the crestHne, which w^as really as clear and 
definite as when figure 10 was taken. In figure 11 the crest- 
line is at the higher end of the instrument (a folding clinome- 
ter, one foot long) lying" on the sand. This view show^s that 
the later efi^ect of the waves on the older part of the ridge was 
to shift the crestline landward a few inches, the stakes show- 
ing its earlier position. Figure 12, facing the opposite direc- 
tion, shows how the spit had lengthened to a crested ridge, 
before the subsiding waves entirely ceased their action. 
The mechanics of the ridge-building involves some undeter- 
mined factors l)ut the general process is evident. The sea- 
ward face of the ridge has the variable curve and angle pro- 
duced by the glide and push of the tongues of water from the 
broken waves. Along the line reached by the greater number 
of tongues of water there is built up an irregular, sinuous 
crest of sand which the water pushes up on its forceful ad- 
vance and leaves there as it softly retires or sinks into the 
thirsty sand. This line is often darkened by magnetite and 
garnet concentrated there, which suggests that there is a ten- 
dency to leave the heavier grains at the crest. The few 
stronger tongues of water which push clear over the crest do 
not destroy or break down or obliterate the crestline but do 
smooth it and straighten it into a clean, sharp line, the summit 
of a low angle. This line is usually as direct as the embank- 
ment of which it forms the crest. Sometimes it may be appar- 
ently straight for several rods, but really makes curves of 
large radius. 
The dimensions of these crested ridges on the Ontario 
shore were not accurately measured. They differ greatly in 
size, varying from a few inches to a few feet in height, and 
from a few feet to a score of feet wide at the base ; wdth a 
length sometimes of a few hundred feet. It would seem that 
with the greater bouyancy of sea water and the greater force 
of sea waves similar structures on the sea beach would often 
attain greater size, and the intervening troughs be cor- 
respondingly broader. However, some of these structures 
seen on the Ontario shore are comparable in dimensions as 
well as form with those found in the Medina sands. 
