Mr. Buckland on the Geology of Madagascar , tsfc. 477 
ship by Governor Farquhar. As these specimens were not collected 
by persons accustomed to inquiries of this kind, they are not ac- 
companied by any geological memoranda, or account of the extent 
and position of the rocks from which they were taken ; they are 
however valuable for the authentic information they give us of an 
unknown region, and as affording a useful index to future investi- 
gations. 
As far as can be ascertained from these specimens, it appears that 
the north-east portion of the island, from which they were taken, 
consists of primitive rocks, sandstone, and trap, presenting a simi- 
lar geological structure with that of the adjacent continent of Africa, 
in the neighbourhood of the Cape of Good Hope. The specimens 
are chiefly from Port Lougui, at the north-east angle of the island, 
and are as follow : 
I. Primitive Rocks. 
The bed of the river Vouluceer, which runs to this port, presents 
varieties of granite very similar to those which occur commonly 
in Europe, e. g. fine-grained grey granite, and large- grained gran- 
nite, containing flesh-coloured crystals of felspar, and resembling 
the blocks of Finland granite that occur near Petersburg, and from 
one of which is formed the famous base of the statue of the Czar 
Peter. Another variety of rock, nearly allied to the granitic series, 
is made up of equal quantities of decomposing flesh-coloured felspar 
and lamellar graphite. This felspar, if separated from the graphite, 
would afford an useful clay for pottery ; there is a specimen of it 
from a spot called EfFetou. The graphite is disseminated equally 
through the felspar in small flat grains resembling dark mica. A 
similar rock occurs on the Danube between Lintz and Passau, and 
supplies Vienna with graphite for black lead pencils. The remain- 
