28 Notices of Memoirs — Prof. C. Wiener — Shell-heaps of Peru. 
is almost, entirely decomposed into kaolin. The laminae or strata of 
the rooks, occasionally of enormous size, and frequently visible in 
tlie bed of the river, follow the direction of the West-African schistose 
group, striking N. — S., and dipping E., with a high angle. The hills 
on both sides of the Ogowe river do not exceed 300 or 400 nieters in 
height, excepting some few isolated heights estimated at 600 to 700 
nieters. The plain of the Okande region lies between 150 and 200 
nieters above the sea-level. The hills and the plain are both covered 
by a yellow, ferruginous, unstratified loani , without traces of organic 
remains, but containing concretions of argillaceous bydroxyd of 
iron and layers of soft white marls. 
Innumerable erratic bloeks of granite are spread over the hills 
and the plains of the Okande region. They have been transported 
and deposited tliere by the waters of the Ogowe, which was far 
more extended during the Diluvial Period than at present. A 
number of Lakes, on both banks of the Ogowe, and only separated 
from it by a strip of ferruginous loam, are the remains of the 
former extension of this river. 
The whole region between the estuary of the Gaboon and the 
delta of Kamma (N’comi) may be regarded as having been linder 
water previous to the deposition of these loams. The waters, sub- 
siding into the valleys, formed rivers, and the more or less inarshy 
tracts of land were gradually covered with the present immense 
virgin forests, obstacles to the investigation of the interior and 
breeding-places of deleterious miasmata. 
IV. — Notes on Shell-heaps on the Coast of Peru, South America. 
By Prof. C. Wiener. (From the Journ. Imper. Geograph. Soc. 
Vienna, 1876, pp. 486-9.) 
[Communicated by Count Marschall, C.M.G.S., etc.] 
0 F these Shell-heaps, or “ Sambaquis,” some lie along the coast, 
otliers 18 to 20 miles inland. They consist of accumulations 
of either whole or broken shells of a Venus, a large Ostrea (now 
living in brackish water), and Corbula. Some of these mounds are 
60 nieters high, and 100 meters in diameter. 
Those composed of fragmeuts are marine beach-deposits, and mark 
the course of the ancient coast-line. These are generally several 
kilometers in length, and tlieir height does not exceed 1^ meter. 
The gradual upheaval of the Peruvian Coast being an undoubted 
fact, the age of these natural accumulations must be admitted to 
stand in direct proportion to their distance from the present coast. 
In fact, two of those most remote from the shore are composed of a 
species of Corbula no longer living on that coast. Prof. Wiener 
concludes, from the results of his measurements, that about fifty 
years ago, the whole ßatone Valley was under water, and that it has 
risen half a meter during the last ten years. The “ Sambaquis ” 
have escaped atmospheric disintegration, both by a crust (occasion- 
ally in the large mounds 40 meters thick), due to the dissolving 
action of carbonic acid and ammonia in the rain-water, and by a 
luxuriant Vegetation. 
