66 The American Geologist. January, issh 
by Hill in Science (Oct. 15, 1897), first described by Marcou in 1857. 
Again, there is some question as to the propriety of including the 
central area of the Black Hills and of other similar mountain ranges 
in a description of laccolitic phenomena, and least of all in the category 
of volcanoes. The axis of uplift of the Black Hills dates from Archaean 
time as old as the protaxis of New England, and has certainly main- 
tained an island in the ocean during all its subsequent geological history. 
There have been later upliftings, both gradual and catastrophic, but there 
i.s no evidence that the Mesozoic and Tertiary beds ever passed intact 
over the summit of Custer and Harney peaks. It is well known that 
the Potsdam sandstone of the region is composed of debris of the older 
rocks, including Potsdam gold placers derived from lodes that must 
even at that date have been elevated above the level of the ocean. There 
are no known laccolites or volcanoes in the region of the Black Hills 
of date earlier than the Mesozoic and probably not earlier than the 
Tertiary. But Bear Butte, on the eastern side, is probably a remnant 
of a late intrusion, while Heenya Kaga, on the west side is an extinct 
volcanic crater later at least than the Carboniferous, and should be 
added to the list of Hill of extinct craters further east than the Spanish 
peaks. N. H. w. 
Beitrage zur Kettntniss einiger pcelceozoischer Fauiien Sud-Amcrikas, 
von Herrn. E. Kayser in Marburg, Hess. (Reprint, a. d. Zeitschr. d. 
Deutsch. geolog. Gesellschaft, 1897.) 
This work is devoted to a description of the Paleozoic faunas of the 
strata of the Argentine Confederation, chiefly its middle and northwest- 
ern parts, and of lake Titicaca in Bolivia. The region is that of the 
high table land on the eastern slopes of the Andes, where these moun- 
tains change from a direct north to a northwest course. 
Dr. Kayser had already described a number of Cambrian and other 
fossils from this region, and tiow adds largely to the number and illus- 
trates his paper with six excellent plates in which the new species are 
figured. 
The Cambrian fossils occur in a fine grained micaceous sandstone, 
having quartz pebbles and seams of slate. The following species are 
described: Liostracus steinmaimi, Ldngiilella ci. ferruginea Salt., L. 
ulftchi L. cf. davisii Salt., Agnostus irugensis [Section Laevigati]. 
From a careful study of the species Dr. Kayser considers that these 
fossils indicate the horizon of the Paradoxides beds. 
The above author also revises his opinion as to the age of the Argen- 
tine Cambrian fauna formerly described by him. On the strength of the 
occurrence of Orthis lenticularis and of an Olenus he had referred this 
fauna to the upper Cambrian, but in concurrence with Dr. W. C. 
Brogger he is now inclined to think that the supposed Olenus should 
be referred to Crepicephalus (Ptychoparia), and that the Orthis alone 
will not confirm the reference to Upper Cambrian. This change he is 
the more inclined to since the fauna described in the present paper, and 
