﻿December ijth, 1904.] PROCEEDINGS. xix 



earthquakes occurred since the beginning of the 19th century are 

 as follows : — June 1, 1801 ; March 17, 18 16 ; November 9, 181 7; 

 October 31, 1818; March 23, 1827; June n, 1833; August 25, 

 1835; June n and 12, 1839; June 21, 1842; March 10 and 

 17, 1843; December 3, 1845; November 9, 1852; October 6, 

 1863 ; September 26, 1864; January 15, 27 and 28, and Feb- 

 ruary 15, 1865 ; February 22 and 23, 1867 ; October 30 and 

 November 22, 1868; March 14, 15 (2 shocks), 25, and 28, 

 1869 ; February 23, March 17, 18, and 22, 1871 ; July 16, 1873; 

 November 14, 1884 ; June 30, 1885; January 5, 1886 ; December 

 i, 1887; February 10, 1889; November 2, 1893; December 

 17, 1896 ; July 9, 1901 (2 shocks); March 24 and June 19, 

 1903; and July 3, 1904. Thus, altogether, 46 earthquakes have 

 been felt in Lancashire during little more than a century. Many 

 of them belong to earthquake centres situated in other counties. 

 The earthquakes of 1863, 1868 (October 30), and 1896, originated 

 in Herefordshire; that of 1852 beneath the Irish Sea; the 

 earthquake of 1893 in Pembrokeshire; and that of June 19, 

 1903, in Carnarvonshire; while the earthquakes of March 24, 

 1903, and 1904, were due to almost simultaneous impulses in 

 two Derbyshire foci, one near Ashbourne, the other near Wirks- 

 worth. There remain, however, a large number which originated 

 in centres situated within or close to the limits of the county, 

 among the most interesting being those of March 17, 1843, 

 March 15, 1869, and March 17, 187 1. 



It is possible that some of the above disturbances may not 

 have been true earthquakes. In all mining districts, shocks 

 occur from time to time, like those felt in the district round 

 Pendleton on February 27, 1899, and April 7, 1900, which are 

 in all probability connected more or less closely with mining 

 operations. In some cases, they may be due to rock-falls from 

 the roof of the workings, but generally, I believe, to small fault- 

 slips when the rock in the neighbourhood of a fault has been 

 deprived of its support by the withdrawal of the coal, etc. 



Of the earthquakes which have occurred since 1899, I nav e 

 now, I think, sufficient descriptions. With these exceptions, 



