34 PHYSICAL FEATURES ETC. 
7000 feet. To the above mentioned series of volcanoes also belong those on the islands 
of Zapatero and Ometepe, in the lake of Nicaragua. The latter, after a long repose, 
burst into renewed activity in 1883, and for seven days continued to spread devas- 
tation, destroying the crops and compelling the people to take refuge on the mainland. 
Several other volcanoes are still more or less active, and in 1835 Coseguina was the 
scene of one of the most tremendous eruptions on record. The outbreak lasted four 
days, during which time sand and ashes were carried to such a distance that they fell 
in Jamaica, Mexico, and Bogota. No rivers of any size flow westward to the Pacific, 
but the Lake of Nicaragua receives, near its outlet, the important Rio Frio from Costa 
Rica, which, at certain seasons, brings down a vast amount of water. Little is known 
of the region of rugged plateaux and savannas occupying fully half the country between 
the lacustrine depression and the Caribbean Sea. A large portion of the low ground 
is said to be covered with dense forest intersected by innumerable streams, all flowing 
eastward to the Mosquito Coast, which is low, swampy, and very unhealthy. 
Mr. Thomas Belt, a mining engineer and a well known naturalist, spent over four 
years at the gold mines of Santo Domingo in Nicaragua, and published an excellent 
account of his travels on his return in 1874. A considerable part of his book is 
occupied with extremely interesting observations on the Indians and the natural history 
of the district through which he passed, and I am indebted to him for the following 
details. Landing at Greytown he proceeded in an open boat up the San Juan River, 
which he describes as having a dangerous bar, over which he had to pass; he then 
entered a wide channel with shallow water and beds of high grass on one side and a 
sandy shore on the other, in which alligators floated about like logs of wood and flocks of 
wading birds were seen in the marshes beyond. Proceeding up the river in still water, 
he emerged into a wider channel with a stronger current. The banks of the river 
were at first low and marshy, intersected by numerous streams fringed chiefly with 
palms and beds of wild cane and grass; further up the banks became higher and 
drier, and plantations of bananas and plantains were noticed in the clearings of the 
forest. About twenty miles above Greytown Mr. Belt reached the Colorado branch 
of the river, which now takes the greater part of the water from the lake to the sea 
by another outlet. ‘There the banks were hidden by high trees laden with creeping 
and twining plants, many of which bore beautiful flowers, while beneath were tree- 
ferns with their light green foliage and siender stems. Higher up he passed the mouth 
of the Chiripo River, which rises in the interior of Costa Rica and joins the San Juan 
about thirty miles above Greytown, It is navigable for about twenty miles from this 
point, after which it becomes a rough mountain-torrent, and a mule track leads thence 
to San José, the capital of Costa Rica. At Castillo, on the river bank, a considerable 
quantity of ‘Ulli’ (ule) or rubber is collected by the Indians, which forms an 
important object of trade. This is obtained from a species of wild fig (Castilloa 
elastica), a plant with large leaves, differing entirely from that found on the banks of 
