1140 General Notes, [ November, 
Dr. Lehmann believes that gabbro is an eruptive rock, younger 
than the granulite but older than the granite. It has been im 
volved in the general metamorphism, and so has assumed schist- 
ose modifications. The Geological Survey of Scotland has re 
cently arrived, independently, at similar conclusions with fi 
to the diorites and amphibolites of Aberdeen and Banff. 
problem in Europe is linked with that presented by similar rocks 
in this country. 
Devonian.—Dr. J. S. Newberry not long ago described the new 
placoderm genus Myzostoma, with two species, variadilis and ter- 
reli (Trans. N. Y. Acad. Sci. 1883). The teeth consist of strong 
and massive tables of bony tissue resembling enamel above, 
disposed in pairs in both jaws. Those of the lower jaw are three 
to six inches long, and more than an inch wide. They 
the teeth of Ceratodus. Only the teeth are yet known. 
Carboniferous—F. Roemer (Zeit. der Deutschen geol. Gesell.) 
describes Belinurus silesiacus from the coal measures of Upper 
Silesia. The cephalic shield is broad and strongly curved, ter 
minating laterally in two horns, and the abdominal shield is 
short. 
Cretaceous—Dr. G. Schweinfurth (Zeit. der Deut. geol. Gesell.) 
contributes a geological map of the strata of the ya 
mountains, near Cairo, showing the nummulitic Cretaceous a 
the Eocene strata with few nummulites, and the Pliocene rè | 
sandstone, rich in pholades. W. Dames (Zeit. der. Deut. = 
Gesell.) contributes a monograph of the genus Ancistrodon. 14è 
teeth called by this name are pharyngeal teeth. 
only found in marine beds, it can scarcely be- i 
among known pharyngeal teeth belonging to marine te Bit 
the only one resembling Ancistrodon are those of Balistes. has 
Plectognaths seldom occur in the older formations, whereas 
cistrodon is found in two formations and in both ne 
No well-grounded conjecture as to the exact 
these teeth can be made. Five species are en 
mosensts, libyanus, texanus, armatus and vicentinus, | 
fourth of which are new. The first three are fro respectively 
vicentinus from the Oligocene of Upper Italy.— 
lignites of the Canadian Northwest are, according t° ©” "i 
Dawson, all of Cretaceous or Tertiary age. Th be 
