50 The American Geologist. July, i898 
it. is another thick series of rocks, named the Fortymile series because 
of its development on the creek of this name. The latter series includes 
alternating beds of marble, from a few inches to fifty feet thick, and 
quartzitic and other schists, with dikes of eruptive granites and diorites, 
and with many quartz veins. 
These two rock series, which are regarded as the principal sources 
of gold, in the placers, are known to be older than the Carboniferous 
rnd Devonian formations of the Cordilleran mountain system, and are 
thought to be pre-Cambrian. The numerous younger rock series of the 
region, and the placer gravels which are the chief object of interest to 
prospectors in the present stage of development of the gold mining, 
are also very fully described. 
The report relates chiefly to the Alaskan possessions of the United 
States, but compri*;es also incidental notes of the Klondike district on 
the British upper part of the Yukon. It is accompanied with many 
maps and sections, and will be of great service to prospectors. For 
their convenient use, also, an abstract of the two Alaskan reports here 
noticed has been prepared, as a separate and abridged publication of 
the U. S. Geological Survey, by Dr. S. F. Emmons, in 44 pages, with 
a large map of Alaska and descriptions of the routes to the gold fields. 
w. u. 
Studies on Ca)nbrian Faiaias. By G. F. Matthew. (Trans. Royal 
Soc. Canada, 2nd ser., vol. 3, sec. 4, pp. 175-21 1, pis. 1-4, 1887.) 
This essay is divided into two parts; the first treats of a new sub- 
fauna of the Paradoxides beds of the St. John group, the second de- 
scribes certain of Billings' Primordial fossils of Vermont and Labrador. 
The fauna described in the first part of the paper is claimed to be equiv- 
alent to that of the upper Paradoxides beds of Sweden. Among the 
fossils is a genus not heretofore recognized in America, viz. Angelin's 
genus Dolichometopiis. Several species of Dorypyge occur in this fauna, 
also species of Anomocare. The prevailing species of Agnosti are 
Longifrontes, Brevifrontes and Laevigati. Several new species of 
Agratilos, one of Liostracns , one of Conocoryphe, one of Ptychoparia 
and one of Dorypyge are described. Many species of the fauna have 
representative forms in Bohemia, Great Britain, etc. 
The author claims that he has established a close relationship be- 
tween this fauna and that of OlenellKS through the genus Dorypyge 
and other types, and suggests that here may be the proper stratigraphi- 
cal place for it, rather than below the Paradoxides beds. 
The second part of the article is taken up with a description of such 
species of Billings' Primordial fossils of Vermont and Labrador as were 
studied in connection with the Cambrian fauna above described. The 
investigation induces Dr. Matthew to think that Billings' species should 
be classed as Middle rather than as Lower Cambrian. This opinion 
appears to be based on the presence of the genera Bathyuriscus (allied 
to Dolichomctoptis), Dorypyge and Anomocare. 
Four plates of figures are given of the new species and varieties 
of the new subfauna, and of the species of Billings' Primordial fauna 
fossils that are discussed in this paper. G. F. m. 
