226 W.-M. Gabb on the Cretaceous rocks of California. 
phydrie acid gas. ter oxydizing the iron, the iron and air 
conia were precipitated together from the nearly neutral solution 
by acetate of soda. e iron was then separated from the air- 
bling that seen in niobic and titanic acids when similarly treated. . 
The color disappears on heating the blue mass in the air. If we 
a 
ART. XXV.—On the subdivisions of the Cretaceous rocks of Calé 
“ fornia; by WM. M. Gass. 
ae the publication of the first volume of the California 
ports fs Paleontology, there have a peared several rather 8 
hoch Bose not altogether good He eem criticisms. These ae 
minated in the publication by the Smithsonian Institution ° 
_ * Imay be : oe 4 oS ju 
spi cater rics 
a ) in the alums obtained from ineral, but its 
tity is very enall-much Ios appre than that of se Peg I. K. 
