134 
JOHN PHILLIPS, F.R.S. 
tions, SO necessary to the preservation of a race, are they restricted 
within narrow Hmits ? or is it possible that in the course of long- 
enduring time, step by step and grain by grain, one form of life can 
be changed, and has been changed to another, and adapted to fulfil 
quite different functions ? Is it thus that innumerable forms of 
plants and animals have been ' developed ' in the course of ages upon 
ages from a few original t}^es ? 
" This question of development might be safely left to the 
prudent researches of physiology and anatomy, were it not the case 
that palaeontology furnishes a vast range of evidence on the real suc- 
cession in time of organic structures, which on the whole indicate 
more and more variety and adaptation, and in certain aspects a gTow- 
ing advance in the energies of life. Thus at first only invertebrate 
animals appear in the cataL^gue of the inhabitants of the sea ; then 
tishes are added, and reptiles and the higher vertebrata succeed ; man 
comes at last to contemplate and in some degree to govern the whole. 
" The various hypothetical threads by which many good 
naturalists hoped to unite the countless facts of biological change into 
a harmonious system have culminated in Darwinism, which takes for 
its basis the facts already stated, and proposes to explain the analo- 
gies of organic structures by reference to a common origin, and their 
differences to small, mostly congenital modifications which are integ- 
rated in particular directions by external physical conditions, 
involving a ' struggle for existence.' Geology is interested in the 
question of development, and in the particular exposition of it by the 
great naturalist whose name it bears, because it alone possesses the 
history of the development in time, and it is to inconceivably long 
periods of time, and to the accumulated effect of small but almost 
infinitely numerous changes in certain directions, that the full effect 
of the transformations is attributed. 
" For us therefore, at present it is to collect with fidehty the 
evidence which our researches must certainly yield, to trace the rela- 
tion of forms to time generally, and ph3^sical conditions locally, to 
determine the life periods of species, genera and families in different 
regions, to consider the cases of temporary interruption and occasional 
recurrence of races, and how far by uniting the results obtained in 
