TWO ANTAGONIST DOCTRINES OF GEOLOGY. 587 



opinion, than to tho doctrine of catastrophes. 1 But Steno, in 1669, 

 approached nearer to this doctrine ; for he asserted that Tuscany must 

 have changed its face at intervals, so as to acquire six different configu- 

 rations, by the successive breaking down of the older strata into inclined 

 positions, and the horizontal deposit of new ones upon them. Strabo, 

 indeed, at an earlier period had recourse to earthquakes, to explain the 

 occurrence of shells in mountains; and Hooke published the same 

 opinion later. But the Italian geologists prosecuted their researches 

 under the advantage of having, close at hand, large collections of con- 

 spicuous and consistent phenomena. Lazzaro Moro, in 1740, attempted 

 to apply the theory of earthquakes to the Italian strata ; but both he 

 and his expositor, Cirillo Generelli, inclined rather to reduce the vio- 

 lence of these operations within the ordinary course of nature,"* and 

 thus leant to the doctrine of uniformity, of which we have afterwards 

 to speak. Moro was encouraged in this line of speculation by the 

 extraordinary -occurrence, as it was deemed by most persons, of the rise 

 of a new volcanic island from a deep part of the Mediterranean, near 

 Santorino, in 1707. 3 But in other countries, as the geological facts 

 were studied, the doctrine of catastrophes appeared to gain ground. 

 Thus in England, where, through a large part of the country, the coal- 

 measures are extremely inclined and contorted, and covered over by 

 more horizontal fragmentary beds, the opinion that some violent cata- 

 strophe had occurred to dislocate them, before the superincumbent 

 strata were deposited, was strongly held. It was conceived that a 

 period of violent and destructive action must have succeeded to one of 

 repose ; and that, for a time, some unusual and paroxysmal forces must 

 have been employed in elevating and breaking the pre-existing strata, 

 and wearing their fragments into smooth pebbles, before nature subsided 

 into a new age of tranquillity and vitality. In like manner Cuvier, 

 from the alternations of fresh-water and salt-water species in the strata 

 of Paris, collected the opinion of a series of great revolutions, in which 

 " the thread of induction was broken." Deluc and others, to whom 

 we owe the first steps in geological dynamics, attempted carefully to 

 distinguish between causes now in action, and those which have ceased 

 to act ; in which latter class they reckoned the causes which have 



" Here is a part of the earth which has become more light, and which rises, 

 while the opposite part approaches nearer to the centre, and what was the 

 bottom of the sea is become the top of the mountain." Venturi's Leonardo da 

 Vinci. 

 " Lyell, i. 3. p. 64. (4th ed.) 3 Ib. p. 60. 



