216 ANALYSES OF ROCKS AND MINERALS, 1880-1908. 
A. Typical ‘‘Virginia slate.’ Average sample. About half chlorite, with quartz 
and perhaps some feldspar fragments. 
B. Siliceous slate, from contact with gabbro, north of Birch Lake. 
C. Slaty phase of the iron formation, Moss mine. 
A. B, Cc. 
62.26 | 78.95 37.11 
16.89 | none 2. 41 
1.76 | 13.89 17.51 
4.55] 1.23] 26.13 
2.95 -18 3.70 
«42 -81 75 
2.29 | none -09 
3.02 | none - 62 
-70 -73 +95 
3. 88 2.21 2.57 
-60 | none - 22 
none 1.59 6.16 
- 20 04 09 
i 11 1.21 
present)........ -73 
| 99.52 | 99.74 100.25 
COLORADO. 
Shales from the Pueblo quadrangle, collected by G. K. Gilbert. 
A, B. Near Nushbaum Spring. 
C. Salt Creek. 
D. Head of Rock Creek> 
E. Near Rush Creek. 
Analyses by George Steiger, record No. 1466. 
A. B. Cc D. E. 
COz..- 
Organic Mattel «exec cceecesese veel eee 
Calcareous shales from Fairplay, Park County. Partial analyses, by W.F. Hille- 
brand, made in the Denver laboratory. 
Insole? ais: s:tcy ay ecctecemeeters 
Fe203, Al2Oz, ete 
FeO, MnO 
MgoO....- Sais ageis cay Si acecenpeSiGss tS etes eecxSee hn oe nes ee eye 
eh spp cscscecocge 2 jseeasus casos age rotate da ea sae esata les ara Ae oe areas NSE 
