232 The American Geologist. April, 1901. 
oped in a belt lying just west of the hornblende schist, trend- 
ing from southeast to northwest from the vicinity of Harrison 
Gulch in Shasta county, across the Hay Fork country and the 
Lower Trinity basin, and crossing the divide into Siskiyou 
county in the New River mountains. It is traversed by the 
south fork of Salmon river below Cecilville, where much of the 
country over a width of ten or fifteen miles belongs to this 
series. The belt probably averages about five miles in width. 
The next principal area is in the Scott Valley region, be- 
tween Fort Jones and Callahan, and extending thence east to 
Shasta valley near Gazelle. The Sacramento caiion cuts a 
number of small areas of this formation between Castella and 
Delta, and it largely occupies the country east of the river to 
and beyond the McCloud river. 
The age of the series is pretty definitely known through 
fossils occurring in it near the Sacramento and McCloud rivers 
and studied by Trask,* Walcott, Smith,"}" Diller, Schuchert.J 
Anderson and others. A small area near Kennett is considered 
Devonian in age, and in limestone near Gazelle has been found 
a fossil fauna indicating still lower Devonian. I understand, 
also, the Devonian fauna occurs in the series in the Scott Val- 
ley region. On the McCloud river a Lower Carboniferous 
fauna is found in the Baird shales and an Upper Carboniferous 
in the McCloud limestone. Prof. J. P. Smith has informed me 
that farther up the McCloud river there are fossils of a Per- 
mian facies. Hence, it appears, that the Lower Slate series 
ranges in age from the Lower Devonian to Permian, and as 
there is no known stratigraphic break in the series, sedimenta- 
tion was probably continuous throughout Devonian and Car- 
boniferous time. Metamorphism in the McCloud region has 
been somewhat less in intensity than in the southwestern Sis- 
kiyou and Trinity areas. It is to be noted, however, that the 
small Devonian area near Kennett more closely resembles the 
series in Trinity county than th^ Carboniferous area in the 
McCloud, and the more aged appearance of the western areas 
may be due not alone to their different situation in the range 
* Report on the Geology of the Coast Mountains, 1855. 
T "The Metatnorphic Series of Shasta conntv, California," Jour, o/" Geo/., 
vol. ii, pp. 588-612. 
t "Discovery of Devonian Rocks in California," Am. Jour. Sci, III Series, 
vol. xlvii, pp. 416-422. 
