SCIENTIFIC SUMMARY. 
91 
In this range of mountains only arc to be found igneous and eruptive 
rocks. — Geol. Mag. Dec. 
The Deltas of the Po, Mississipi, and Ganges. — Mr. A. Tylor has compared 
together the deltas of these rivers and the alluvial plains above them, and 
states that a parabolic curve drawn through the extremities of each river, 
and through one point of its course, nearly represents its longitudinal sec- 
tion — the greatest deviation being 30 feet in some of the largest deltas. — 
Geol. Mag. Dec. 
Glaciers in Central France. — M. Martins has examined the valley of 
Palheres in the eastern part of the granitic massif of the Logere, and foimd 
evidence of the former existence of a glacier. It was a glacier of the second 
order, one of those which, limited to the cirque which contains them, do 
not descend into the valley.’ The crest of the vast cirque into which the 
valley of Palheres rises is capped by an elevated ridge, the summits of 
which, to the north and east, are formed of a white refractory granite. 
M. Martins found the fields and woods round the hamlet of Costeiladi 
within the eirqiie to be sown with innumerable erratic blocks, extending far 
up both the contreforts of the mountain. No signs of polished and striated 
surfaces or grooved pebbles were to be expected, as the base and contreforts 
of the valley are formed of mica-schist, too soft, of course, to streak granite 
or to take and retain a polish. 
The Foraminifera of KosteJ. — Herr Karrer has laid before the Vienna 
Academy his monograph on the fauna of foramicifera of Kostej, a place 
situated in the mountains forming the south-eastern boundary between 
Hungary and Transylvania. This fauna includes nearly 250 species, a 
great number of which are new, and particularly remarkable — such as 
Dactylopora miocenica, Peneroplis lantei^ and numerous and beautiful [Mi- 
liotides. The fauna is that of a deposit of marine origin, corresponding 
to the miocene stage of the Vienna and Hungary basins, and marking thus a 
horizon intermediate between the oldest deposits of this middle tertiary sea 
(Baden clay) and the littoral formations of more recent date (calcaires ley- 
fhiens). — FPistitut, Dec. 2. 
Ormerod's Geological Index . — A second edition is, we believe, now nearly 
complete, and contains the papers in the Quarterly Journal for 1868. Mr. 
Ormerod’s address is Chagford, Exeter, and geologists who find errors in the 
Index are requested to communicate with the author of the Index. 
The genus Trimerella (Billings) is the subject of a paper (translated) by 
Dr. Lindstrom in the Geological Magazine for October. The specimens de- 
scribed were found in limestone beds in the upper Silurian of Gotland. 
The author, having received drawings and descriptions of the specimens of 
Mr. Billings, found in Canada, declares that the two series of specimens are 
the same, those of Gotland being the more perfect. A plate accompanies 
Dr. Lindstrom’s paper, in which the shells are well figured. The greatest 
peculiarity of the genus the author thinks consists in the presence of two 
siphons or tubes that penetrate the shell along the median axis of the 
valves or on both sides of it. These siphons, by degrees, taper off, and cease 
in the vicinity of the apex of the valves ,* their openings are of an ovate 
oblique form on the interior surface of the valves, and almost in the centre. 
An elevated shield, hiding the continuation of the siphons in its interior, is 
