704 The American Naturalist. [August. 
that Ceylon had been separated from the peninsula either through 
the agency of currents or partial submersion. But modern in- 
vestigations have disproved this, and it is now tolerably certain 
that Ceylon was never connected with India, but is one of the 
few remaining vestiges of a huge continent which stretched in 
almost boundless expansion to the south, far beyond the equator 
into the distant regions of the Pacific. The geological features 
of Ceylon are veiy unlike those of Southern India ; the config- 
uration of the mountains, the stratification of the rocks and their 
geological ages are quite different. In Ceylon we have a moun- 
tain region, rising more or le.ss abruptly from the lowlands, and 
composed almost entirely of metamorphic rocks, chiefly gneisses, 
schists and slates, resting on an ancient granite. The formation 
is essentially Archsean : there is an almost total absence of any 
of the fossiliferous strata of the more recent periods, and an 
entire absence of Tertiary rocks. The only limestone found is 
an ancient dolomite of crystalline .structure, in which every trace 
of organic remains — if ever existing — has been obliterated. 
Now most of the continent of Southern India consists of recent 
rocks, and it would seem that at the commencement of the 
Tertiary period the greater part of the peninsula was .still covered 
by the sea, but that in the south a great continent extended east- 
ward and westward, connecting Malacca with Arabia. The 
Himalaya range then only existed as a chain of islands, and did 
not, till a much later age, become elevated to its present propor- 
tions, a change which took place during the same revolution that 
raised the great plains of Siberia and Tartary. While these 
gigantic land masses slowly rose from the ocean depths the huge 
continent between the tropics underwent a simultaneous depres- 
sion. This continent, in all probability, once connected the 
distant islands of Ceylon, Sumatra and Madagascar. 
In Ceylon we find about 38 species of birds which are unknown 
in continental India, but these ver>' birds occur in Sumatra, 
Borneo and others of the Sunda Islands. The insects of Ceylon 
are more closely related to those of the Malay Archipelago than 
to those of India. The elephant of Ceylon is not identical with 
that of India, but presents characteristics which are also po.s- 
