118 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
historic period it has been very slight indeed. The recession of the sea 
at the rate of “ten fathoms in thirty years” as given by Capanema 
is quite out of the question. 
CHANGES WITHIN RECENT GEOLOGIO PERIODS. 
Views of former writers. —It is somewhat remarkable that all those 
who have seen this coast and expressed views about its history have 
thought it to have been elevated within recent geologic times. These 
writers are, Barão de Capanema,! Liais, Hartt, and J. Clarke 
Hawkshaw.* 
Thomaz Pompeo de Souza Brasil, in his valuable Ensaio Estatistico da 
provincia do Ceará (р. 49), says that at the Barra do Pacotí in Ceara, “as 
in Bahia and Rio de Janeiro, proofs are seen of the elevation of the coast,” 
but he does not say what these proofs are. 
It is but fair to these writers that their views and their reasons for 
holding them should be given. On the other hand, it is but just to 
recall the fact that a theory becomes really important only when it is 
supported by adequate evidence. 
I shall therefore give very briefly what the authors cited regard as 
evidence of the geologically recent elevation of the coast, and at the same 
time my own reasons for looking upon the bulk of this evidence as 
unsatisfactory. 
Hartt presents tangible evidence of elevation along the coast about 
Rio de Janeiro, and for some distance north of there. This evidence 
consists of sea-urchin holes, and old water-lines above tide-level on the 
island of Maricas, near Rio, on the great conical hill at Victoria, and on 
the island of Sant’ Anna. 
In the article cited Hawkshaw speaks of conclusive signs that the 
coast has recently risen” and of “ unmistakable signs . . . of a recent ele- 
vation of the coast,” but he does not say what these signs are. 
The following are adduced by Liais as facts in support of the elevation 
theory : — 
1. The schistose structure of the reef rocks. 
1 Trabalhos da Commissão Scientifica de Exploração. 1. Introducgäo, р. 
cxxi, exxxvii. Rio de Janeiro, 1865. 
2 E. Liais. Climats, géologie, etc. du Brésil, р. 256-261. Paris, 1872. 
E. Liais. L’Espace Céleste, ed. 2, р. 545-548. Paris (18817). 
Compt. Rend., 1860, L., р. 762-768. 
3 Geology and physical geography of Brazil, p. 35, 36, 42, 71-72, 844. 
* Quar. Journ. Geol. Soc., 1879, XXXV., р. 241-243. 
