540 Proceedings of the Pioyal Society 
significance, lie could, as it were, read off the geology of a country 
after a few traverses only, when most men would have been 
puzzling over their first section. This was the secret of his broad 
generalisations regarding the geological structure of a large part of 
Europe,—generalisations which, though of course requiring to be 
corrected and modified by subsequent more detailed investigations, 
still remain true in the main, and still astound by their marvellous 
grasp and suggestiveness. The leading idea of his scientific life 
was to establish the order of succession among rocks, and through 
that order to show the successive stages in the history of life on 
our globe. With the more speculative parts of geology he meddled 
little ; nor did he ever travel outside the bounds of his own science. 
He early recognised the limits within which his powers could find 
the fullest and most free development, and he was seldom found 
making even a short excursion beyond them. 
“ The special part of his work on which his chief title to fame 
rests is undoubtedly his establishment of ‘ The Silurian System.’ 
Before his time, the early chapters of the history of life on our 
globe had been but dimly deciphered. William Smith had thrown 
a new flood of light upon that history by showing the order of suc¬ 
cession among the secondary rocks of England, and had done more 
than any other man to dispel the prejudices with which the 
doctrines of Werner seemed naturally to fill the mind. But the 
rocks older than secondary, to which Werner had given the name of 
‘ Transition,’ remained still in deep Wernerian darkness. Sir 
Eoderick Murchison saw that it might be possible to bring order 
and light out of these rocks, even as had been done with those of 
more recent origin; and that a double interest would attach to 
them if, as he supposed, they should reveal to us the first begin¬ 
nings of life upon our globe. Choosing a part of the broken land 
of England where the rocks are well exposed, he set himself to 
unravel their order of succession. Patiently year after year he 
laboured at his self-appointed task, communicating his results 
sometimes in writing to his friends, sometimes in the form of a 
short paper to the G-eological Society of London, until at last, in 
1838, he gathered up the whole into his great work,' c The Silurian 
System.’ In that book the early chapters of the history of life on 
the earth were first unfolded, and a system of classification was 
