30 'I'll' American Geologist. July, 1894 
quite different from that east of Squawcfeek. On Campbell's 
creek the rock overlying the limestone appears to be a pseuclo- 
diorite, associated with others in a highly metamorphic con- 
dition. Nine miles above Campbell's the limestone strata are 
separated by layers of a hard feldspathie rock of a greenish 
color. Twelve miles to the north the overlying rock is a green 
to purplish conglomerate, very compact and hard. On Chat- 
berdown creek occur quartzite, green conglomerates, and di- 
orite. The great body of the rock seems semi- to fully crys- 
talline. The field is undoubtedly an interesting one for the 
Study of metamorphism. 
The uppermost horizon of fossiliferous strata on the Mc- 
Cloud occurs about twenty miles above the Fisheries on the 
east side of the river. Here is found a calcareous argillite 
rich in several species of Productus, besides other forms, 
which according to Mr. Smith belong in the upper portion of 
the Carboniferous. These argillitic limestones and the asso- 
ciated shales are embraced under the designation, McCloud 
shales. 
The Devonian of the Sacramento River. What is perhaps 
the oldest fossiliferous formation in this region is found west 
of the Sacramento river and near the station of Kennett. 
Here occur four or more detached limestone areas associated 
with green rocks and slates: areas probably once more or less 
continuous, but which have been broken apart by intrusive 
masses. The strike and dip of the inclosing rocks is exceed- 
ingly irregular. One bod}* of fossiliferous limestone is crossed 
by the old trail from the Squaw creek to Kennett. The other 
most important ones lie on the mountain side between the 
Backbone creeks. The fossils found here are exclusively co- 
rals and the number of species is not large. Much of the 
limestone seems formed almost wholly of the coral fragments. 
In places a network of coral stems weathers out, almost com- 
pletely covering the surface of the rock. The age of this 
limestone is probably Devonian, according to determinations 
made by the U. S. Geological Survey. 
Geological Results. Mr. Diller has added largely to our 
knowledge of the geology of Shasta county. Several locali- 
ties of Triassic and Jurassic as well as Carboniferous fossils 
have been reported by him. The age of the main portion of 
