1884. ] Geology and Paleontology. 819 
foothold for sponges, various ccelenterates, &c., which in return 
die and bring up the bottom to the level of reef coral growth, 
This, taking place on a submerged bank,would produce the atoll- 
form of island, which would tend to widen by death inside, and 
by the consequent solution of the dead coral by the carbonic acid 
of the sea-water. Special cases, such as elongate chains of atolls, 
Fourn. Roy. Microscopical Society, April. 
GEOLOGICAL NEws.—Carboniferous——Dr. R. H. Traquair (Geol. 
Mag., Feb.) describes Aganacanthus striatulus from selachian 
spines found in the Blackband ironstone of Borough Lee, near 
Edinburgh. the January number of the same magazine, 
Dr. Traquair describes Ctenacanthus costellatus, a shark from the 
Lower Carboniferous rocks of Eskdale, Dumfriesshire. It appears 
to be a Cladodont. In the same issue Dr. Traquair describes 
Elonichthys ortholepis, a ganoid fish from the Lower Carboniferous 
of Eskdale, Dumfriesshire——— Mr. J. Young notes upon the 
hinge line of Spirifera trigonalis, a denticulated structure like 
at upon the hinge line of Arca. He regards these denticles as 
originally formed of aragonite, which is harder than calcite. In 
the fossils, however, the aragonite has decayed, and has been 
replaced by a coarser calcite (Geol. Mag., Jan.)—-—At a recent 
meeting of the London Geological Society, J. W. Davis described 
the fishes from the Yoredale series at Leyburn. Of the thirty- 
four species twenty are identified with known Carboniferous lime- 
stone forms, one, Megalichthys hibberti, is a coal-measure species, 
while the remaining thirteen are described as new. Eight of 
these are regarded as types of new genera. Dr. E. Tietze 
(Jahrb. Kais. Kon. Geol. Reichanstalt, 1884), contributes an 
extensive account of the geology of Montenegro. Twenty- 
three peaks rise to elevations varying from 2000 to 2500 
meters. All the principal formations from the palæozoic to 
the quaternary can be identified with tolerable certainty, but 
their members are not so well made out. The palzozoic strata 
consist largely of black or quaternary strata, occur east O 
Dulcigno, east and north of the Scutarie-see, and at various 
rolated points. Marine neogene strata are only found between 
Dulcigno and the coast, and fresh-water strata of similar age do 
hot enter the boundaries of the little principality. The various 
rtiary strata are grouped along the Adriatic shore, and include 
nummulitic beds. The Cretaceous strata occupy the largest area, 
wale in the north the Trias is largely developed——Among the 
70st recent of the memoirs of the Museum of Comparative 
gy is an account by C. E. Hamlin, of the results of an ex- 
rt tion of the Syrian molluscan fossils, chiefly from Mount 
OL. XVIII.—No. vIn. 52 
