490 Scientific Intelligence. 
of the formation; “ while the rock of the northwestern side contains 
fragments of magnesian limestone,” a rock occurring in the older 
formations near by on that side. The exposure of Silurian mag- 
nesian limestone within the area of the sandstone, and other facts 
are stated to favor the view of a comparatively small thickness 
for the formation. 
The report is accompanied by a handsome colored geological 
map of the State. 
5. Note on the occurrence of fossils in the Triassic and Juras- 
sic beds near San Miguel in Colorado ; by R. C. Hir1s.—The 
fossiliferous portion of the Triassico-Jurassic beds of the Upper 
San Miguel is situated in lat. 37° 58’ N., long. 107° 50’ W., near 
the town of San Miguel city, and extends east from that point 
along the flank of San Miguel park about two and a half miles. 
The fossils occur in the upper portion of the red sandstone beds 
thickness. r stratum, in which the Pterophyllum was 
found, is a fine-grained micaceous red sandstone with a schistose 
cleavage. ten ud-cracks and raindrop pits, also 
impression 
fossil will probably be restricted to places where small depres 
twenty feet to forty feet of bituminiferous limestone at the ag 
followed by a few feet of hornstone and several hundred feet 0 
gray sandstone. I have not observed any fossils in “e series, 
be 
one. 
The rock of the lower portion of the red sandstone earn a 
often shaly and readily separable into fragments of conchoida 
ss of 
these beds, but it is not less than 1,000 feet. Bee 
g section of these rocks is showed upon the pernis 
where they extend for six miles along the river between Hermo 
and Animas City, upon the Dolores near Rico, on the peer 
pahgre below Ouray and less extensively on nearly every strea 
tributary to the Animas and San Juan. 
