1. Cherry, R. D., Taylor, S. R., and Sachs, M., Nature, 187, 680 (1960).
2. Friedman, I., Thorpe, A., and Senftle, F., Forty-first Annual Meeting, American Geophysical Union, April 27–30 (1960), Program Abstracts, 60.
3. Barnes, V. E., Univ. Texas Pub. No. 3945, 477 (1940).
4. Iddings, J. P., “Igneous Rocks”, 2, 114 (John Wiley and Sons, Inc., 1913).
5. Chao, E. C. T., Shoemaker, E. M., and Madsen, B. M., Science, 132, 220 (1960).