1876.] Geology and Paleontology. 439 
the present time. The conclusions reached may be briefly stated as 
follows: First, all tertiary mammals had small brains; second, there was 
a ual increase in the size of the brain during this period; third, this 
increase was mainly confined to the cerebral hemispheres, or higher por- 
tion of the brain ; fourth, in some groups, the convolutions of the brain 
have gradually become more complicated ; fifth, in some, the cerebellum 
and olfactory lobes have even diminished in size. There is some evidence 
that the same general law of brain-growth holds good for birds and rep- 
tiles from the Cretaceous to the present time. 
Some additional conclusions in regard to American Tertiary mammals, 
so far as now known, are as follows: First, all the Ungulata from the 
Eocene and Miocene had upper and lower incisors; second, all Eocene 
and Miocene mammals had separate scaphoid and lunar bones; third, all 
mammals from these formations had separate metapodial bones. 
In conclusion, Professor Marsh stated that his work in the field was 
now essentially completed, and that all the fossil remains collected, and 
in part described, were now in the Yale College Museum. In future, he 
‘should devote himself to their study and full description; and hoped at 
no distant day to make public the complete results. 
Extinct Corat Reer ar Banta. — The Geological Commission of 
Brazil has just been examining with a great deal of interest, in the Bay 
of Bahia, an extinct reef, which would need little more than an inter- 
mingling with geological strata to make it resemble some of the lime- 
stone formations of the United States. Opposite the city of Bahia is 
the large and long island of Itaparica, which extends in nearly a north- 
east and southwest direction. It is formed of cretaceous rocks which ` 
appear along a large portion of the shore, and, outcropping underneath 
the water, afford good foundations for coral growth. The reef we have 
just mentioned is a fringing one, extending along the middle part of the 
Southeast side of the island, for a distance of about eight nautical miles, 
and distant from the shore from one eighth to one quarter of a mile. It 
apparently follows a line of outcrop of cretaceous sandstone, and is 
€ up mainly of a few species of corals and of nullipores, the latter 
form seeming to contribute the greatest amount of material to the reef. 
Running along the reef, we find that it varies in width from sixty to 
nearly two hundred feet; at extreme low tide its height above the water 
is about four and one half feet, and this height does not vary much 
throughout its entire length. At high water the reef is covered by the 
sea, which almost constantly breaks upon it, and, as the entire reef faces 
the ocean, in times of storm a heavy line of breakers is formed outside 
Openings, or barras, through which small boats can enter and find a safe 
harbor within, At the southern end it becomes broken up and lies in 
ached portions. The reef has sometimes a single elevation above 
