Paper read by Dr. John B. Trask before the California Academy of Natural Sciences, San Francisco, March 30, 1857:
"This earthquake, or more properly speaking, the series of shocks that began on the night of the 8th in this city [San Francisco], and which continued in the south part of the State during the following day and night of the 9th, was probably the most extensive of any on record on this portion of the Pacific coast, excepting, perhaps, that of the wave of the Simoda earthquake in December, 1854. The linear distance over which we are able to trace its course, amounts to six hundred and two miles, and its breadth, so far as now ascertained, is two hundred and ninety miles."