166 J. HOPKINSON 



the latest, on 15tli March, 1905 ; while the point of origin of the 

 slight shocks on 20th November, 1887, is uncertain. 



Not far beneath us, probably nearer the surface in the Valley 

 of the Lea than here, but even there some thousand feet down, is 

 a ridge of rocks of Palaeozoic age, consisting of Wenlock Shale 

 dipping southwards at a high angle, of Upper Devonian beds 

 dipping at a smaller angle, and of red rocks which may be either 

 Old or New Red Sandstone or Carboniferous, -with about the 

 same dip. This ridge is believed to run nearly east and west, 

 and if so would transmit earthquake shocks to us on the one 

 hand from the volcanic districts of the Continent of Europe, 

 and on the other from strata liable to faulting which form 

 the rather insecure grovmdwork of Herefordshire and the 

 surrounding district. 



We are thus as it were between two fires, but the Cretaceous 

 and Eocene beds which lie upon the rigid Palaeozoic rocks are of 

 such a yielding nature that they would form a kind of biiffer to 

 a deep-seated shock, and although it is on record that the bed 

 of the River Thames was so far upheaved or the flow of water 

 so much held back by an earthquake in 1158 that it was walked 

 over dry-shod in London, it is unlikely that we shall ever 

 experience in Hertfordshire or Middlesex such a shock as that 

 which John Hardyng witnessed in England in 1382, when 

 " Th earth quake was whiche that tyme I sawe, 

 That castelles, walles, toures, and steples fyll, 

 Houses and trees and cragges fro the hyll." 



Y. Appendix. 



1. List of Earthquakes recorded in Hertfordshire, with references 

 to the Bibliography which follows. 



1250, Dec. 13.— St. Albans and the Chilterns : Matthew 

 (1567), Paris (1571), Holinshed (1577), Stow (1580), Camhridge 

 (1750), Anon.— Hist. Rev. (1752), Anon.— Hist. Ver. (1815), 

 Williavis (1822), Perrey (1850), Mallet (1853), Loive (1870), 

 Prestwich (1870), O'BeiUy (1885, 1886), Roper (1889). 



1551, May 25. — Albury : Stow (1565) ; Bennington and 

 Allmry : Stoiv (1580), Stowe and Howes (1615). 



1750, Feb. 19.— Hertford : Gent. Mag. (1750), Lond. Mag. 

 (1750), Scots Maq. (1750), Milne (1841), Meldola and Wliite 

 (1885), O'Beilly (1885, 1886), Home (1887), Boper (1889). 



1750, March 19. — Northaw, Grobions, near Hatfield, 

 Panshanger, Hertingfordbury, Hertford, Wai'e, and Cheshunt : 

 Cowper (1750), Stulceley (1750), Cambridge (1750), Gent. Mag. 

 (1750), Scots Mag. (1750), Milne (1841), Perrey (1850), Mallet 

 (1853), Lowe (1870), Meldola and White (1885), O'Beilly (1885, 

 1886), Meldola (1886), Home (1887), Boper (1889). 



1755, Nov. 1. — Eoyston, Albury, and near Bishop's Stortford 

 (Patmore Hall and Wickham Hall) : Butherford (1756), Perrey 

 (1850), Mallet (1853), Meldola (1886). 



