1 877.] 
Southern Hemisphere » 
329 
been local, but must have been cosmic. “ When,” he says, 
“ Switzerland was bridged across from range to range, by a 
mass of ice stretching southward into Lombardy and Tus- 
cany, northward into France and Burgundy, the rest of 
Europe could not have remained unaffected by the causes 
which induced this state of things.”* Agassiz was thus 
the founder of the theory of a “ Glacial Period,” and in 
Great Britain, in Scandinavia, and in North America, evi- 
dence was soon found, and has been ever since accumulating, 
attesting the truth of his grand generalisation. 
He was not likely to be mistaken as to what constituted 
a moraine, but he found none in the great valley, and he 
says himself that he had not here the positive evidence that 
had guided him in his previous glacial investigations. f Not 
so, however, with regard to his discovery of the marks of 
glaciation on the mountains of Ceara. Here, only about 
three degrees south of the Equator, he found undoubted 
moraines blocking up the valleys, and the evidence of gla- 
cial aCtion was to him as clear as in the valleys of Switzer- 
land, of Scotland, and of the Northern States of America . % 
This is the nearest point to the Equator at which 
glacial moraines have been found. On the other side of the 
line I found huge moraines in the northern part of Nicara- 
gua, near the boundary between it and Plonduras, in lat. 
1 3 0 47' N. || This is the farthest south that glacial aCtion 
has been traced in the northern hemisphere. Prof. W. M. 
Gabb has informed me that in his geological researches in the 
mountains of Costa Rica he found no evidence of glaciation. 
Between the moraines of northern Nicaragua and those of 
the mountains of Ceara there is an area comprising about 
17 0 of latitude, and including most of Nicaragua, the whole 
of Costa Rica, of Columbia, of Equador, and of the great 
valley of the Amazons, in which no certain signs of glacia- 
tion have been seen. This wide region includes several 
large zoological sub-provinces, characterised by highly pecu- 
liar tropical genera, and a wealth of species not met with 
elsewhere on the continents to the north and south. Within 
this area are large groups of inseCts the extreme forms of 
which are linked together by a series of gradations, and 
every district has its representative forms of types that run 
through the whole. But as we travel south from the un- 
glaciated districts lying between lat. 14 0 N. and lat. 3 0 S. the 
* Geological Sketches, Second Series, p. 29. 
f Ibid., p. 207. 
% A Journey in Brazil, by Mrs. Agassiz, p. 456, 
|| Naturalist in Nicaragua, p. 260. 
