Editorial Coinniciil. 321 
drccl .111(1 fifty UK'kTS. and a lrniL;tli of from a few ])aC(.'S to 
several kilometers. 
3. They acc(ini])any the shore line with many and great 
interru])tions, from north Ceara to I'orto Seguro. a distance 
of 2000 kihjmeters. 
4. With unimportant exceptions the reels do not occur 
along" the BraziHan coast beyond these limits. 
5. They usually stand across the mouths of s'treams and 
estuaries, fonuing perfect natural breakwaters for the small 
harbors behind tlieiii. Sometimes they follow the shore, either 
on the iieach or at a short distance from it. 
0. They are all nearly straight. W'licii crooked, their 
curves are gentle. 
7. The structure and position of the reefs and the ani- 
mal remains they contain show that they have been made by 
the lilhilication of beach sands in place. 
8. \\'hen stone and coral reefs occur together, the stone 
reefs are inside or landward of the coral reefs. It is possible, 
however, that there may be buried coral reefs in some cases 
to the landward of some of the stone reefs. 
9. The coral reefs are now growing over and ui)on the 
stone reefs in some places, while at other ])laces there are 
stone reefs overlying dead coral reefs. 
10. In general appearance, elevation, and position, the 
standstone reefs bear a striking resemblance to the coral reefs. 
The cause and history of these stone reefs were found to 
contain the elements of a great many ])roblems'. some of them 
reaching back of the present and .re(|uiring a study of the 
geographic development of the entire coast line, a study that 
has never yet been attempted. 
After giving a general sketch of the geology of the Bra- 
zilian coast line and a detailed description of the reefs them- 
selves at numerous chief hxalities. the author enter^ upon an 
^nquirv as to their cause. Their structure was found out to be 
that of beach sand, loose and irregularly bediled below but 
cemented into firm rock above, through a thickness of. three 
or four meters, tlie cement being carbonate of lime. It seems 
plain that some cause peculiar to the Brazilian coast nuist be 
largelv responsible for such persistent off-shore beaches, else 
thev would be a mere common phenomenon. In but few other 
