8 J.D. Dana—Rock notation for Geological Diagrams. 
I. Rocks whose essential constituents are quartz, mica, orthoclase,. 
singly or in combination. 
1. Massive quartzyte (or quartzose sand- 
stone). 
2, Conglomerate. 
3. Thin-bedded quartzyte (or sandstone). 
4, Micaceous quartzyte. 
5. Feldspathic quartzyte. 
6. Phyllyte (argillyte). 
7. Hydromica schist. 
8. Quartzytic or arenaceous hydromica. 
schist. 
9. Very quartzytic hydromica schist. 
10. Mica schist (with little or no feldspar). 
11. Quartzytic or arenaceous Mica schist. 
12. Very quartzytic Mica schist. 
ee 
3. Gneiss, thin-bedded. 
4. Gneiss, thick-bedded. 
— 
— 
5. Granite. 
_ 
6. Granulite (mica-less granite). 
Pte ert + 
Gaines 17. Felsyte. 
Fitts 18. Quartz-felsyte. 
+ae Casaen 
ip fnaated fetes trtestrorere 19 
Rtrtitsisdesteccet: is pikseicn 
Ppregeress ce rers srt+s 
20. nar vpn ark : same as 19, with the addition of the dot 
artz. 
ecko mica schist: same as 13 with the addition of a 
rule beneath cui line of symbols. 
