asts of America south of the Plata during
the two succeeding years. The almost entire absence of trees in the
pampas of Uruguay, the provinces of Buenos Ayres [now Argentina], and
Patagonia is remarkable.

Fifteen miles from the Rio Negro, the principal river on the whole line
of coast between the Strait of Magellan and the Plata, are several
shallow lakes of brine in winter, which in summer are converted into
fields of snow-white salt two and a half miles long and one broad. The
border of the lakes is formed of mud, which is thrown up by a kind of
worm. How surprising it is that any creature should be able to exist in
brine, and that they should be crawling among crystals of sulphate of
soda and lime!

The valley of the Rio Negro, broad as it is, has merely been excavated
out of the sandstone plain; and everywhere the landscape wears the same
sterile aspect.

_II.--Fossil Monsters of the Pampas_

The pampas are formed from the mud, gravel, and sand thrown up by the
sea during the slow elevation of the land; and the section disclosed at
Punta Alta, a few miles from Bahia Blanca, was interesting from the
number and extraordinary character of the remains of gigantic land
animals embedded in it. I also found remains of immense armadillo-like
animals on the banks of a tributary of the Rio Negro; and, indeed, I
believe that the whole area of the pampas is one wide sepulchre of these
extinct colossal quadrupeds. The following, which I unearthed, are now
deposited in the College of Surgeons, London.

(1) Head and bones of a _megatherium_, the huge dimensions of which are
expressed by its name; (2) the _megalonyx_, a great allied animal; (3)
the perfect skeleton of a _scelidorium_, also an allied animal, as large
as a rhinoceros, in structure like the Cape ant-eater, but in some other
respects approaching the armadilloes; (4) the _mylodon Darwinii_, a
closely related genus, and little inferior in size; (5) another gigantic
dental quadruped; (6) another large animal very like an armadillo; (7)
an extinct kind of horse (it is a marvellous fact in the history of the
mammalia that, in South America, a native horse should have lived and
disappeared, to be succeeded in after ages by the countless herds
descended from the few introduced with the Spanish colonists); (8) a
pachydermatous animal, a huge beast with a long neck like a camel; (9)
the toxodon, perhaps the strangest animal ever discovered; in size it
equalled an eleph