EARTHQUAKES 293 



subjected to earthquakes ; but some features such as pinnacled rocks 

 with insecure bases and steep hillsides covered with soil give evi- 

 dence that a region has been free from violent shocks for many cen- 

 turies. For example, New England has probably been free from dev- 

 astating earthquakes since glacial times, as the almost precipitous, 

 soil-covered slopes of many hills and mountains show. This is also 

 borne out by the occurrence of perched bowlders in very insecure 

 positions. 



REFERENCES FOR EARTHQUAKES 



Davison, Chas., — A Study of Recent Earthquakes, 1905. 



Dutton, C. E., — Earthquakes in the Light of the New Seismology, 1904. 



Fuller, M. L., — Our Greatest Earthquake: Pop. Sci. Monthly, Vol. 69, 1906, pp. 



76-86. 

 Geikie, A., — Textbook of Geology, Vol. 1, 4th ed., pp. 358-377. 

 Gilbert, G. K., — The Investigation of the San Francisco Earthquake: Pop. Sci. 



Monthly, Vol. 69, pp. 97-115. 

 Hobbs, W. H., — Earthquakes, an Introduction to Seismic Geology, 1907. 

 Lawson, A. C., et al., — The California Earthquake of April 18, 1906: Report of the 



State Earthquake Investigation Commission, Carnegie Institution of Washington. 

 Tarr, R. S., and Martin, L., — Recent Changes of Level in the Yakutat Bay Region, 



Alaska: Bull. Geol. Soc. America, Vol. 17, 1906, pp. 29-64. 

 Wright, C. W., — The World's Most Cruel Earthquake: Nat. Geog. Mag., Vol. 20, 



1909, PP- 373-396. 

 Carnegie Institution Publication 87, Vol. 1, Plate 15 and Atlas. 



