| ON THE FACTS OF EARTHQUAKE PHANOMENA,. 49 
et colores aquarum, βίους Babylone lacus estate rubras habet diebus XI. 
Et Borysthenes estatis temporibus ceruleus fertur, quanquam omnium 
aquarum tenuissimus: ideoque innatans Hypani. In quo et illud mirabile, 
Austris flantibus superiorem Hypanim fieri.”—Plin. Nat. Hist., lib. xxxi. 30. 
Again :—“ Sepe motu terrarum itinera flaminum turbantur et ruina in- 
terscindit aquas, que retentz novos exitus quzrunt, et aliquo impetu faciunt 
aut ipsius quassatione terre aliunde alio transferuntur........ quod accidisse 
ait Theophrastus in Coryco monte, in quo post terrarum tremorem nova vis 
fontium emersit.”"—Senec. Nat. Quest., 1. iii. L1. 
Tt will be necessary to go somewhat into detail, not only to record some 
of these facts, but to show how they depend upon the accidental features of 
country as affected by earthquake motion. 
These phenomena were presented in great variety and upon a peculiarly 
grand scale in the great Calabrian earthquake; and we are chiefly indebted 
to Sir William Hamilton, in his account of them addressed to the Royal 
Society of London, for first pointing out the true relation that they bore to 
the earthquake itself. 
_ The general geological features of the Calabrian plain which have been 
_ already given, the great tabular surface of clay, sand, and soft decomposed 
_ rock, divided by deep ravines and river courses, must be now borne in mind by 
the reader. The following then are some of the principal secondary phzeno- 
| mena that were there observed, and which are more or less common to all 
| earthquakes on land. 
lst. Vast landslips take place. 
_ The shock transferred horizontally through the plain (either as the normal 
_ or wave at right angles to this), on reaching the steep escarpments of the 
_ valleys, shook down enormous masses of these; the deep clay banks above split 
into fissures, extending to a great depth, and the weight of superineumbent 
_ stuff often forced out the base of the escarpment into the middle of the ravine 
or valley, so that the upper part of the bank fell nearly perpendicularly (in 
_ some cases 500 feet), and was deposited with all its trees and crops growing 
upon it atthe bottom. In other cases, where the escarpments were less steep, 
Jandslips in the more ordinary form took place, and the upper lands slid down 
Over a rough inclined plane of previous ruin, sometimes leaving nought but a 
' chaos of upturned trees and crops, with mud and soil and sand at the bottom ; 
| and at others, where the thickness of the mass detached was greater, or the sur- 
face over which it was launched was more uniform, landing the whole upper 
ace safely down some hundred feet, with even houses, standing firm on the 
_ surface and all the crops uninjured: people descended unhurt on such sin- 
gular and mighty vehicles; but often the surface over which the slip was 
_ launched was not a plane, but curved or twisted, so as to change the direction 
Οἵ motion of the moving mass; and here the mass was sometimes broken to 
Pieces, but at others its surface was only twisted and distorted in rude copy 
f that over which it had passed and on which it came to rest. Thus, straight 
5 of elm-trees and of olives became curved, furrows straight from the 
ough became twisted and contorted. 
_ Childrey, ‘ Britannia Baconica,’ gives several instances taken from Cam- 
_ den’s pages, of the effects of great landslips in altering the form and directions 
| ‘furrows, hedge-rows, landmarks, &c., and one especially of twenty-six acres 
of land which so moved in Herefordshire in 1571. (Hooke, Dis. of Earth- 
quakes, p. 309.) Another great English landslip is recorded in Baker's ‘ Chro- 
_Nhicle,’ p, 419, near Kynaston, in Herefordshire. These are the phenomena 
" ao appears to have mistaken for evidences of vorticose shocks. 
=) 1850. E. 
