156 D. DALE CONDIT 
portion which, by its mineral content, shows derivation from the 
crystalline rocks. A number of minerals entirely wanting in the 
old sandstones are found fresh and little altered. Garnet, diopside, 
augite, enstatite, hypersthene, hornblende, actinolite, cyanite, and 
free grains of magnetite are abundant in the drift. Of these garnet, 
diopside, augite, enstatite, hypersthene, and cyanite are not found 
in the old sandstones and the others are rare. The former presence 
of abundant ferromagnesian minerals is indicated by chlorite, 
saussurite, and other alteration products. 
The character of the glacial sand type is well shown by a fine- 
grained sand from near Sandusky, Ohio. The bed is regarded as 
an off-shore deposit in Lake Warren.* 
MINERALS IN ORDER OF ABUNDANCE 
1. Quartz 10. Tourmaline 
2. Garnet 11. Zircon 
3. Diopside 12. Limonite 
4. Hornblende 13. Kaolinite 
5. Enstatite 14. Apatite 
6. Microcline 15. Sericite 
7. Plagioclase 16. Epidote 
8. Orthoclase 17. Magnetite 
9. Hypersthene 18. Rutile 
The sand is made up of angular grains with surfaces that show 
recent fracture. The size grades from 0.05 mm. diameter down 
to mineral dust. There is little limonite coating on the grains. 
Garnet, diopside, enstatite, hypersthene, hornblende, and feldspars 
are the principal accessory minerals and none of these are much 
decomposed. 
The characters of the three great sand types may be sum- 
marized as follows: The rock sands (all Paleozoic) are made up 
of travel-rounded grains more or less firmly cemented. The min- 
erals are those of a stable nature together with some which have 
been derived by the alteration of less stable original minerals. 
Ferromagnesian minerals are almost entirely wanting. The 
residual sands and outwash deposits derived from erosion of the 
sandstones are made up of products that represent the final 
« Frank Leverett, Monograph 41, U.S. Geol. Surv., Plate XXII. 
