8 NOTES OF A BOTANIST 
on the morning of August 21, with the fag-end of 
the ebb, which carried us down beyond the islands 
in front of Para, and then the flood-tide, aided by 
several oars, carried us up all the way to Caripi, 
where we arrived well on in the afternoon. The 
river Para is at least ten miles wide there, appear- 
ing more like an inland sea or large lake, and the 
coast of the isle of Marajo is dimly seen on the 
opposite side, without any intervening islet. The 
shore is a spacious and gently sloping beach of 
white sand, which at low water we could traverse 
in an upward direction for a distance of several 
miles, without any obstacle except having to ford 
the igarapes which here and there intersect it. At 
a little way up, the beach begins to be bounded by 
low cliffs of a ferruginous, coarse-grained sandstone 
in horizontal strata, the same as is to be seen near 
Para, on the river Guama and elsewhere, being, in 
fact, the common building stone ; but great was my 
surprise to see also large detached blocks of a 
honeycombed rock, with a reddish vitrified surface, 
quite resembling masses of slag, and plainly of 
igneous origin. I saw one instance of the contact 
of the two rocks, where the trap had penetrated 
the clefts of the sandstone and partially fused it. 
We shall see that I afterwards came on the same 
sort of blocks at various points in the Amazon 
valley. 
The estate of Caripi embraced, I believe, many 
square leagues, but with the exception of a small 
space kept open near the house for the grazing of 
cows and goats, and of a few mandiocca clearings 
away at the back, tenanted chiefly by Indian 
squatters, the ground was all forest. Caripi was, in 
