s 
Re. 
a “extent “cannot be less than two hundred thousand to three 
~ thousand square miles, i. e., greater than the whole area € 
_ Or nearly double the area of California.” He believes | 
ae lava to have issued from fissures, some in the Coast 
a par in the Cascade and Blue Mountain Ranges. Th 
- meeting of the Academy of Natural Sciences of Philadelphia, Prof. 
~ common green and brown species. He stated that they had been 
ence,” what he regards as the most extraordinary lava-flood in 
greater inequalities of surface, while in northern Oregon and Wi 
` ington it becomes an absolutely universal flood, beneath which 
_ whole original face of the country, with its hills and dales 
_ tains and valleys, lies buried several thousand feet. It co 
suas the whole of Oregon, Washington and Idaho, and ra 
h. 
244 GEOLOGY. oe 
couver island. .... . This insect, though one of our Pacific 
coast varieties, has nevertheless a wide range. I have seen spec- — 
imens from Victoria, northern and middle California, San Diego, — 
cape St. Lucas, and San Blas, Mexico.” if 
On pp. 24 and 40, Bost. Proc., xvi, Gorytodes uncanaria Guen: — 
should read Platæa Californiaria H.-Sch. and Gorytodes trilinearia — 
should read Platæa trilinearia. — A. S. PACKARD, Jr. ‘ 
j a 
Tpentiry or our Hypra wiru European Specres.—At a late — 
Leidy made some remarks on our native Hydra, and described the — 
Nees as distinct eis from the green and brown ones of 
absorb the chlorophyl and reject the silicious shell. 
vours Arcella. 
GEOLOGY. 
Tue GREAT Livan oF tue West. — Prof. J. eo 
scribes in the March number of the “ American Journal of: 
world. “ Commencing in middle California as separate streams, 
in northern California it becomes a flood flowing over and com- 
pletely mantling the smaller inequalities, and flowing around 
greater portion of northern California and northwestern * 
into Montana on the east and British Columbia on the north. 
