LYELL’S GEOLOGICAL DOCTRINES. 127 
development, and effected this reform in a manner similar to 
that in which, thirty years later, Darwin in his work reformed 
the science of Biology. Lyell’s great treatise, which radically 
destroyed Cuvier’s hypothesis of creation, appeared in the 
same year in which Cuvier celebrated his triumph over the 
nature-philosophy, and established his supremacy in the 
domain of morphology for the following thirty years. 
Whilst Cuvier, by his artificial hypothesis of creation and 
his theory of catastrophes connected with it, directly ob- 
structed the path of the theory of natural development, 
and cut off all chance of a natural explanation, Lyell once 
more opened a free road, and brought forward convincing 
geological evidence to show that Cuvier’s dualistic concep- 
tions were as unfounded as they were superfluous. He 
demonstrated that those changes of the earth’s surface, 
which are still taking place before our eyes, are perfectly 
sufficient to explain everything we know of the development 
of the earth’s crust in general, and that it is superfluous and 
useless to seek for mysterious causes in inexplicable revolu- 
tions. He showed that we need only have recourse to the 
hypothesis of exceedingly long periods of time in order to 
explain the formation of the crust of the earth in the simplest 
and most natural manner by means of the very same causes 
which are still active. Many geologists had previously 
imagined that the highest chains of mountains which rise on 
the surface of the earth could owe their origin only to 
enormous revolutions transforming a great part of the earth’s 
surface, especially to colossal volcanic eruptions. Such 
chains of mountains as those of the Alps or the Cordilleras 
were believed to have arisen direct from the fiery fluid of the 
interior of the earth, through an enormous chasm in the 
