
A NATURALIST IN BRAZIL. 5 
North America the last great upheaval was greater in the 
north than in the south. Facts seem to show that in South 
America it was just the reverse. 
About half-way between the cities of Bahia and Rio de 
Janeiro, and distant about forty miles from the mainland, 
there is a little group of islands, which, lying right in the 
way of navigation along the coast, and surrounded by dan- 
gerous reefs, have long been known as the Abrolhos, or 
* Open-your-eyes” Islands. 
If we make a section across the country from the coast 
mountains, which separate the provinces of Minas Geraes and 
Bahia, to the sea, and then continue it to the Abrolhos, we 
shall have one like the following : — 
SierradosAymores 06 b b d b = Abrolhos, d 

a, Gneiss; b, Tertiary strata; c, Cretaceous strata; d, Coral reefs. 
In this section the New-Red Sandstone and Cretaceous 
beds do not appear on the main-land, at least so far as I have 
seen, and usually, as on the river Mercury, we find the Ter- 
tiary clays and sandstones lying immediately over the gneiss. 
But at the Abrolhos Cretaceous rocks appear, for the islands 
are seen to be composed of beds of shale, sandstone, etc., 
similar in character to those of the Cretaceous farther north. 
These islands stand about in the middle of the submerged 
border of the continent, which is here at least seventy miles 
wide. This submarine shelf is overspread by Cretaceous 
rocks, which, at the Abrolhos, have been broken and uplifted 
so as to form a little group of islands. 
The Abrolhos consist of four principal islands, and two 
little islets. These are arranged close together in an irregu- 
lar circle. Allare quite high, the height of the principal one, 
Santa Barbara, being 33.22 metres (about 109 feet). This is 
the largest, and is three-quarters of a mile inlength. On its 
