Xliv PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



US to explain geological monuments. "We must have recourse," he 

 says, " to other causes, both organic and inorganic, of a more ener- 

 getic and even paroxysmal character*." 



On this subject I must make two preliminary remarks : First, that 

 our present inability to decipher some of the monuments of past 

 ages by a key derived from the effects of causes now acting, ought 

 never to be adduced as an argument of much weight in favour of the 

 paroxysmal theory ; for it might with equal or greater propriety be 

 urged as a reason for believing in the adequacy of existing causes, or 

 their identity with those of former times, since no one doubts that 

 we are ignorant of the nature of many subterranean and suboceanic 

 changes now in progress. If therefore there was nothing obscure or 

 mysterious in geological phsenomena, if they simply presented to us 

 a picture of objects as familiar as the lavas of Vesuvius or the cal- 

 careous tufas of mineral springs, or the newly-formed deposits of a 

 delta seen at low water, we should be entitled to suspect a great want 

 of analogy between the ancient and modern processes at work above 

 and below the earth's surface. We should then be entitled to ask, 

 where are the nether-formed and deep-sea formations of the olden 

 time ? Where are the signs of those changes brought about in the 

 bowels of the earth corresponding to such as are now in progress in 

 regions inaccessible to human observation? Why have not the 

 causes which have upheaved mountains and deeply fissured the rocks, 

 or which have denuded large areas, revealed to us ancient stratified 

 and unstratified rocks, wholly distinct from any which we now see 

 generated by ordinary volcanic action or formed in lakes and shallow 

 seas. Secondly, it should be thoroughly understood that the decision 

 of the question at issue can in nowise be determined by simply com- 

 paring the magnitude of the changes brought about in historical 

 times with those of antecedent periods. It may be safely affirmed, 

 that the quantity of igneous and aqueous action, — of volcanic eruption 

 and denudation, — of subterranean movement and sedimentary depo- 

 sition, — not only of past ages, but of one geological epoch, or even 

 the fraction of an epoch, has exceeded immeasurably all the fluctua- 

 tions of the inorganic world which have been witnessed by man. But 

 we have still to inquire whether the time to which each chapter or 

 page or paragraph of the earth's autobiography refers, was not equally 

 * Axchiac, Hist, des Progres, &c. tome i. pp. 209, 670. 



