One Was 4 Feet 8 Inches In Diameter,
And The Wood Must Have Been Soft Like That Of The Baobab,
For There Were Only Six Concentric Rings To The Inch.
As the semidiameter
was only 28 inches, this large tree could have been but 168 years old.
I found also a piece of palm-tree transformed into oxide of iron,
and the pores filled with pure silica.
These fossil trees
lie upon soft gray sandstone containing banks of shingle, which forms
the underlying rock of the country all the way from Zumbo to near Lupata.
It is met with at Litubaruba and in Angola, with similar banks of shingle
imbedded exactly like those now seen on the sea-beach, but I never could
find a shell. There are many nodules and mounds of hardened clay upon it,
which seem to have been deposited in eddies made round the roots of these
ancient trees, for they appear of different colors in wavy and twisted lines.
Above this we have small quantities of calcareous marl.
As we were now in the district of Chicova, I examined
the geological structure of the country with interest, because here,
it has been stated, there once existed silver mines. The general rock
is the gray soft sandstone I have mentioned, but at the rivulet Bangue
we come upon a dike of basalt six yards wide, running north and south.
When we cross this, we come upon several others, some of which
run more to the eastward.
Enter page number
PreviousNext
Page 902 of 1070
Words from 258996 to 259245
of 306638
