ON THE AMAZON. 67 
you must do the best you can to separate the varieties. What they 
have under the name of Maniva-macacheira is a distinct species, the 
Manihot Aypi of Pohl, the root of which is edible when simply 
boiled. I ate some of it, which these people gave me, and found it 
excellent, as mealy as a potato, but possessing more substance, and, I 
believé, far more nourishing. 
The promontories stretching here and there into the bay of Marajó 
are all rocky, the rocks sometimes ten feet high, consisting partly of the 
usual reddish-grey sandstone of the country, but principally of large 
amorphous masses of reddish honey-combed rock, quite resembling the 
dross of an iron-furnace. These I do not hesitate to pronounce vol- 
canic. I have seen one instance of the contact of the two rocks: the 
trap had penetrated the clefts of the sandstone and partially fused it. 
If any of our geological friends would like to see a mass of this rock, 
Lean probably send one when I return to Para ; but I found it too hard 
to break off a fragment. 
At Caripi I visited, also, a deposit of shells at a considerable dis- 
tance from the river; but I have since obtained better specimens brought 
from a similar deposit at Salinas, which I send, along with a separate 
notice. 
The old low trees along the beach were filled with Orchideous 
plants, and other epiphytes, besides several Loranthacee. Of the 
Orchidee only one or two of the smaller species were in bloom; but 
I gathered of all I could find, and now send them, in order that when 
they flower you may ascertain whether they include any novelties. 
After a fortnight’s stay, we proceeded directly from Caripi to Tanaü, 
in a galiota of Mr. Campbell’s. The distance is 50 miles, and, in con- 
sequence of our men missing the tide, the voyage occupied us from 
two o’clock in the afternoon of one day until noon of the next. 
Tanaii is about thirty miles south of Para, and on a branch of the Rio 
Para, called the Rio Acarà. This is, comparatively speaking, a drook, 
being only 800 yards wide; yet it is navigable for the largest vessels 
at a distance of five days’ journey from its mouth, and its actual source 
is in the province of Maranhaon. The ground at Tanaii offers an 
agreeable contrast to the unvaried plain about Para. Immediately 
behind Mr. Campbell’s house, hills rise to the height of 130 feet, and 
there are loftier ones behind in the forest. Here and there, too, one 
comes unexpectedly on a ravine filled with palms and ferns. Of the 
K 2 
