72 Mr. Mattet on the Dynamics of Earthquakes. 
the direction contrary to its course, must, in various places, have produced the 
effect of the retardation, stoppage, or reflux of the current for a few moments, 
as in the case of the South Carolina earthquake of 1811, where the course of 
the Mississippi was temporarily arrested below New Madrid ;* or, as in the great 
Calabrian earthquake, where the courses of many rivers were arrested at the 
moment of the passage of the first shock, the waters drying up all at once, as the 
ridge of the earth wave dammed them up above, and caused their waters to run 
proportionately rapidly off, down stream, behind the earth wave. They almost 
immediately began to run again as usual, but with increased volume, owing to the 
short withholding of their waters. This phenomenon was particularly remarked 
in the river Metramo, at the bridge of Rofarno. 
Dolomieu, in his Dissertation on the great Earthquake in Calabria Ultra of 
1783 (a scarce work, of which a limited number of copies were printed at Rome, 
in 1784), records the above, and several other remarkable facts ascertained per- 
sonally by him, none of which have hitherto been explained, but of which I now 
propose explanations accordant with my general theory. 
The great Calabrian plane consists of a vast, deep, diluvial deposit, reposing 
upon the hard granite and slates which form the mountain chain of the Appen- 
nines in that country. These plains, which have a gentle slope seaward, 
are cut into deep ravines and valleys, of greater or less magnitude, in all direc- 
tions, by the excavations of the rivers and drainage of high and plain lands, so 
that the vast mass of loose material composing the latter is, to a certain consi- 
derable depth, divided, as it were, into a number of small, insulated table lands, 
by intervening glens with steep escarpments. 
Dolomieu compares it to a number of cubes, or rather of irregular flat masses 
of damp sand, placed near each other upon a flat table ; and he describes the gene- 
ral effect of the earthquake as like that which would be produced upon these 
disconnected masses, by shaking the table with a horizontal motion, namely, a 
general tendency to level the whole—to break down the escarpments of the 
valleys, and fill them. Hence, the most capricious changes of the face of the 
country resulted from the earthquake: valleys were dammed across in a moment 
by the ‘slipping’ of vast masses of their loose escarpments, often bearing 
upon them still rooted woods, vineyards, and olive yards, and even houses. 
* Lyell, vol. i. p. 470. 
