Sto/ie Reef at Rio Grande Do Norte. — Branner. 343 
open umbrellas. These and other fantastic shapes with keen 
edges and points, render walking on the surface rather dif- 
ficult in places. 
Over a large part of its surface, and especially on the 
outer and inner faces where the rock is least exposed to the 
atmosphere, it is covered with algs, corallines and barna- 
cles to such an extent that the true character of the rock 
is not apparent. Upon being broken however in any part 
the rock is found to be a brownish yellow and ver\' hard 
sandstone ringing under the hammer and containing large 
numbers of shells and water-worn quartz pebbles. A remark- 
able thing about the shells found in this reef rock, is that 
they seem to be of the same species as those found upon the 
present sand beaches in large numbers. 
The reef is widest at the fort, and narrowest along its 
northern end, from the fort to the bar. Beginning at its 
southern end it has a bearing of N., 9^ E. for about a mile. 
The first 3000 feet of this portion of it, resembles a jagged 
line of rocks and loose slabs, though here and then it is un- 
broken. Beyond this, for 2700 feet, it is one unbroken mas- 
sive wall, with a gently sloping surface, its inner or land- 
ward face broken square off, and'its outer edge protected 
by huge blocks broken from the main body and tossed 
about at all sorts of angles by the surf. Near the north end 
of this part of the reef it runs N., 17*^ E. and at this angle 
reaches a break about 180 feet wide and filled with loose 
blocks. • 
From this point the reef continues northward for 1800 
feet to another break 80 feet wide, 1500 feet further north 
is another gap, and the direction of the reef changes to N., 
4° E. There is no other break from this point to the end of 
the reef at the bar. 
The directions given are magnetic bearings taken in June, 
1899. It is worthy of note that while the course of this re- 
markable rock does change somewhat, in the main it is al- 
most straight. 
Another noticeable feature is that it seems to be accom- 
panied throughout a part of its length by an inner reef that 
lies to the landward of and appears to dip beneath the main 
reef. It has been stated that the fort is built upon a wide 
