C. D. Walcott—Paleozoie Rocks of Central Texas. 433. 
its sandstones and limestones in order to study the fauna more 
thoroughly and to illustrate Dr. Shumard’s species. A section 
was also found on the west side of Honey Creek valley that 
shows the contact with the Llano group below, the passage 
into the Silurian above, and the thickness of the Silurian up to 
the base of the Carboniferous. 
The section gives 245 feet of sandstone and 625 feet of lime- 
stone; all marked by the presence of an abundant Upper Cam- 
brian (Potsdam) fauna; Lingulepis, Orthis, Agnostus, Ptycho- 
paria and Dicelloce ‘ 
The upper beds of the Potsdam become compact, hard and 
have a little included cherty matter. The fauna terminates 
here as far as observed and it is not until over one thousand 
feet of limestone are passed through, that recognized fossils 
again occur. The fauna is then of the type of that of the 
Calciferous group. A number of fine specimens were collected 
of the genera Ophileta, Straparollus, Murchisonia, Orthoceras 
and Bathyurus. 
massive bed of limestone, sixty feet thick, rests on the 
Silurian beds, 1145 feet above the upper beds, carrying Potsdam 
fossils, and directly above it limestones of a slightly different 
character carry common Carboniferous fossils, viz: Productus 
semireticulatus, P. Nebrascensis, P. Prattenianus, Streptorhynchus. 
erenistria and Bellerophon sp. 
A vertical fault, parallel with the strike of the strata, breaks 
the continuity of the section about 300 feet above the summit 
of the Silurian, and the study of the Carboniferous was not 
taken up in detail. 
On the Colorado river, in San Saba county, a collection of 
cephalopod shells, of the genera Goniatites, Nautilus and 
Orthoceras, was obtained from the Carboniferous, and on the 
San Saba river a quantity of corals were collected. 
The results obtained are: additional data on the Potsdam 
section and fauna; the Silurian section and fauna; Carbonifer- 
ous fauna; the geologic relations of what has long been known 
as an Archean area and which is now referred to the Came 
brian, and the determination of the age of the granite of Burnet 
county. 
