1895.] Geology and Paleontology. 479 
(3). The precambrian Radiolarians are the oldest known rhizopods, 
and of the Sponges the phtanites are the first in point of time. (Revue 
Scientifique Feb., 1895.) 
The zinc deposits in the Galena limestone of the Upper Mississippi 
are unique in that they occur in practically undisturbed strata that 
show no evidence of metamorphoric action, and are found in crevices 
of comparatively limited extent downward. The ores are the car- 
bonate, sulphide and silicate. As to their origin, it is suggested by A. 
G. Leonard that the zine comes from the limestones in which occur the 
crevices. It was deposited along with the sediments by the waters of 
the Silurian sea into which the metallic salts were washed from pre- 
existing land surfaces. After deposition in the limestome beds the 
zine was concentrated in the crevices by the action of drainage water 
percolating through the metal-bearing beds. (Proceeds, Iowa Acad. 
Sci. Vol. I, Pt. IV, 1894.) 
Mesozorc.—In commenting on the Sauropodous dinosaur recently 
found in Madagascar, Mr. Lydekker notes first, that it belongs to a 
hitherto imperfectly known genus, first described from the Jurassic 
rocks of England, under the name Bothriospondylus; secondly, the 
lateral cavities of the vertebree had no connection with any honey- 
combing of the interior, and, finally, this fossil completes the evidence 
that gigantic sauropodous dinosaurs ranged over Europe, India, Mad- 
agascar and North and South America during the Jurassic and Creta- 
cic periods. From these facts Mr. Lydekker infers that, since the 
whole world was inhabited by such closely allied reptiles, the great 
continents were intimately connected with each other, and the evolu- 
tion of distinct regional faunas and the separation of large southern 
island-continents (now, for the most part reunited with more northern 
lands) took place during the early Cenozoic period. (Knowledge, 
March, 1895.) 
The remarkable resemblance of the jaws and dentition of the Creta- 
ceous fish Erisichthe to those of the Upper Jurassic genus Hypsocormus 
extends to the pectoral fins and the axial skeleton, so that Mr. A. S. 
Woodward concludes that Erisichthe is not a “Teleostean” in the 
ordinary acception of the term, and that none of its known characters 
warrant its separation from the family to which the Jurassic genera 
Hypsocormus and Pachycormus belong. (Ann. Mag. Nat. Hist. 
1894.) 
Crenozoic.—A revision of the Cenozoic deposits of the Texas Coastal 
Plain has been made necessary through the accumulation of new 
