e not necessarily thinner, is not so solid. In cooling
it has cracked and left fissures or caverns or jumbled strata of
softer material between harder rocks, so that it is peculiarly subject
to earthquakes."

Maj. Clarence E. Dutton, U. S. A., retired, the most famous American
expert on seismic disturbances, said it was probably the greatest
earthquake that has occurred in this country since 1868. He declared
that it undoubtedly would be followed by disturbances of less
intensity in the same quarter. He stated most emphatically that the
eruption of Vesuvius had no bearing whatsoever on the disturbance on
the Pacific Coast.

J. Paul Goode, a professor in geology in the University of Chicago,
attributes the cause of the Frisco earthquake to the Sierra Madre
mountains, but not in a volcanic way, for he also claims that lava had
nothing to do with the California shock. The shocks, he showed, can be
attributed to mountains without volcanoes in their midst. The Sierra
Madres are growing, he said, and for this reason they have shaken the
city of San Francisco. He says that the gradual growing of mountains
causes the underlying blocks of the earth's crust to slip up and down
and shape the top of the earth in their vicinity when they fall any
great distance.

His ideas upon the subject are: "I figure that the earthquake which
caused so much damage in San Francisco came from what we call the
focus of disturbance. This focus at San Francisco is seven miles below
the surface of the earth. As the Sierra Madre mountains grow, a
phenomenon which is constantly going on, the blocks of earth below
change positions; as a large block falls a series of shocks travels,
up and down much the same way as the rings in the water travel out
from the point at which a pebble strikes. When the vibration reaches
the surface crust a severe shaking of the country adjacent is the
result.

"From the actions of the earth in April of 1892, when such a severe
shock was felt in San Francisco, I have no doubt but that a second
earthquake will follow closely upon the one of yesterday, as the
second followed the first in 1892. In that year the first came upon
the 19th of April and the second upon the 21st."

Of 948 earthquake shocks that have been recorded in California
previous to 1887, 417 were most active in San Francisco. The
seismographs which record the merest tremors and determine the place
of the shock show that 344 have occurred since 1888. Half