BT 
. 
Genus Agnostus.— Vogdes. 
usually granite, slates and quartzite accompanied by iron-stained 
quartz, boulders and pebbles, presumably from the veins them- 
selves, frequently black magnetic sands, and more or less fine allu- 
vials. These beds attain great thickness, often resting on the bed 
rock which may be two or three hundred feet below the surface. 
Placer beds may exhibit a stratified arrangement of the gravels, 
boulders and sands, the gold confining itself to particular horizons. 
The proportion of fine detrital matter and clays, in a placer claim 
varies very much. There may be a good deal of intermingled 
dirt and sands, and frequently the bed may consist almost wholly 
of pebbles and boulders. In this latter instance, I believe the 
gold gradually sinks down in the bed, when unobstructed by clays 
and subject to continual action of percolating waters, to a lower 
level. The arrangement of the gold in streaks in the bed, or its 
uniform distribution depends less perhaps on the proximity of 
the bed to the source, than to the force of distribution and de- 
nudation; beds several miles removed from their source fre- 
quently having the gold arranged in streaks, by water action. 
[Notes on Palwozoic Crustucee No, 2.|* 
ON THE NORTH AMERICAN SPECIES OF THE 
GENUS AGNOSTUS. 
By A. W. Voapes, Fort Canby, Wash. 
HISTORICAL SKETCH OF THE GENUS AGNOSTUS. 
The earliest known species of this genus was described and figured 
by Bromell in 4729, Lithographia Suecana, Actis Liter., Suecie, Upsal, 
vol. 2, p. 527, under the name of Vermiculd vagipennes. The author mis- 
takes the fossil for an insect and figures Agnostus pistformis from the 
Olenus schist of Andrarum, Sweden. For a_ period of almost 
one hundred years this was the only representative of a genus, to which 
Brongniart gave the name of Agnostus, taking for its type Agnostus pis? 
formis from Linné’s Hntomolithus pisiformis, Syst. Nat. Ed. x11, p. 160. 
Dalman uses the same species for the type of his new genus /attus in 
1826, Palzeaden p. 257. ; 
In the year 1828, Dalman, Vetensk, Akad, Arsber, p. 136, described a 
new species from Gothland under the name of Batius lwvigatus, anda 
new variety from Andrarum, as attus pisiformis var. spiniger. The 
next contribution to our knowledge of this genus was made by Beyrich 
in 1845, Ueber Bohm Trilobiten, p. 44. The author adds two new 
species to the list from the Paradoxides zone of Bohemia, under the 
*No. 1 of these notes is published in Trans. St. Louis Acad. Sci., Vol, 
v, 1891. 
