640 General Notes. 
of these masses as substantially a single Tertiary eruption. Mr. 
Becker claims to have found additional reasons for maintaining the 
existence of diabase, and also for dividing the pyroxene andesite 
into two distinct outflows, separated by a long interval of time. 
At Steamboat Springs, about six miles from Virginia City, occurs 
an extensive series of sedimentary beds, nearly vertical, with a 
strike following the general direction of the Sierra. Andesites and 
basalts have broken through and overlie these beds, which are with- 
out trace of fossils, and are evidently pre-tertiary. Indeed, they 
appear to be as old as the rocks determined as Jura-Trias by the 
geologists of the fortieth parallel. These sedimentary beds contain 
pebbles of the exact character, both physically and mineralogically, 
with the east wall of the Comstock lode, determined by Becker as 
porphyritic diabase. The presence of these pebbles in beds of pre- 
tertiary age proves that there must be real pre-tertiary diabase 
somewhere in the neighborhood of Mt. Davidson. This locality is 
substantially in the same district as the Comstock lode, and, accord- 
ing to Mr. Becker’s investigation of the faulting action on the Com- 
stock, formerly received the drainage from the diabase area at 
Virginia. 
In the thirty-fourth part of Palewontographica, E. Holzapfel 
describes the molluses of the Cretaceous of Aachen, prefacing his 
account with descriptions of the strata and lists of the species con- 
tained in each. 
Dr. Rust (Paleontographica, Band xxxiv.) adds an importi 
contribution, illustrated with eight plates, to the knowledge of 
Radiolaria of the Cretaceous. Whilst in the Jura the oldest en 
bed in Dr. 
Rusts monograph, 59 are found in the Neocomian, 109 in the 
Gault, and only six in the upper stages of the system. 
Cæxozorc.—Prof. J'Prestwich (Quart. Jour. Geol. Soe.) P iog- 
table of the accepted classification of the Eocene series 1m nd 
land, Belgium, and the Paris basin, and states his Leave) 
some adverse conclusions. The sands and marls of Heers 
