NATURE 
[Nov. 9, 1882 
sketches of New Zealand, New Britain, New Guinea, and the 
Caroline Archipelago are exceedingly well drawn and valuable. 
He brings about Ico cases of ethnographical specimens intended 
for the new Ethnological Museum at Berlin. 
THE AIMS AND METHOD OF GEOLOGICAL 
INQUIRY? 
N entering upon the duties of this Chair I can hardly do 
better, perhaps, than try to set before you what are the 
primary aims and general bearings of that branch of natural 
science which we are about to study, and to indicate the nature 
of the problems with which it deals. In doing so I will endea- 
your at the same time to point out the method of research and 
the mode of reasoning which we must pursue if we are to be 
‘successful investigators. Geology (in which comprehensive 
term I include mineralogy and paleontology), is concerned in 
the first place with observations of minerals, rocks, ard fossil 
organic remains, and in the second place with the inferences 
which may be drawn from those observations. Its object is 
thus not only to note the nature and position of the various 
materials which constitute the solid crust of our globe, but by 
processes of inductive and deductive reasoning to ascertain how 
minerals and rocks have been formed and caused to assume the 
different appearances which they now present. In few words, 
then, our science might be defined as an inquiry into the history 
or development of the earth’s crust, and of the several floras 
and faunas which have clothed and peopled its surface. It thus 
treats of the genesis of oceanic and continental areas—of muta- 
tions of climate—of the appearance and disappearance of suc- 
cessive tribes of plants and animals. More than this, in reveal- 
ing the past it throws strong light upon the present, and has, 
perhaps, more than any of the cognate sciences, tended to revo- 
lutionise our conceptions of nature, ard to lead zoologists and 
‘botanists iato fruitful fields of inquiry which their own proper 
studies, no matter how assiduously prosecuted, could never have 
enabled them to reach. 
Dealing, as geology does, with the operations of Nature in the 
past, it is obvious that before we proceed to interpret the record 
of the rocks we ought to have a clear knowledge of the mode in 
which Nature works at present Without this preliminary 
knowledge, it is just as hopeless to attempt to decipher that 
record as it would be to endeavour to understand a page of 
Greek without having first mastered the grammar and rudiments 
of that language. We must turn our attention then, at the very 
outset, to a study of those great forces by the action of which 
the crust of our globe is being continually modified. It is 
essential that we learn to appreciate the work done by the atmo- 
sphere, by frost and snow and ice, by rain and underground 
water, by rivers and lakes, by the sea, by plants and animals, 
and by the subterranean forces, before we can hope to recognise 
the different parts which those various agents of change have 
performed in the past. All geologists are agreed upon this, and 
are ready to acknowledge it as the chief article of their faith. 
Nevertheless, this obligatory article has received different inter- 
pretations. Some, for example, have held that the present 
condition of things must be taken as the exact type of all the 
phases through which the earth’s surface has passed, during the 
different stages of which we have any recognisable records pre- 
served to us in the stratified rocks of the globe. They admit 
that countless modifications of land and sea have taken place— 
that the climate of particular areas has varied again ard again— 
that the subterranean and volcanic forces have manifested them- 
selves with unvarying intensity, now in one place, now in 
another—but they hold that all these changes have been accom- 
plished upon the same scale and at the same rate as at present, and 
that, as a consequence, the development of floras and faunas, so 
far as that is dependent upon physical conditions, has proceeded 
no more rapidly in former times than in our own day. They do 
not, indeed, deny that in the very earlicst stages of the earth’s 
history the agents of geological change must have acted with 
greater intensity than now, but of such a period, they tell us, 
we have no certain evidence treasured up in the sedimentary 
rocks, or at least such evidence, if it should exist, has not yet 
been detected. Only allow time, they say, and the constant 
drop will wear away the hardest stone. The gradual elevation 
* The Inaugural Lecture at the opening of the Class of Geology and 
Mineralogy in the University of Edinburgh, October 27, 1882, by james 
Geikie, LL.D., F.R.S. L. and E., Regius Professor of Geology and 
Mineralogy in the University. 
of land, which is now going on in certain parts of the globe at 
so slow a rate that some have been inclined to doubt whether 
there is any movement at all, would nevertheless suffice in time 
to lift tracts now within tide-wash into stupendous table-lands 
and mountains, Nor is it necessary, we are assured, to suppose 
that the apparent evidence of convulsive rending and displace- 
ment of strata, which is often so conspicuous in the heart of 
great mountain-chains and munges, is really any proof of par- 
oxysmal action, All the rupturing and confusion which we may 
note among the Alps and not a few mountain-regions, may 
quite well have been brought about, we are informed, in the 
most gentle and gradual manner. 
Other theorists, again, are of opinion that, while the agents of 
change have necessarily been through all time the same in kind, 
they have yet varied again and again in d , and that the 
present moderate condition of things cannot therefore be taken 
| as an exact type and pattern of all preceding phases in the 
world’s history. They cannot allow that the elevation of moun- 
tain-chains and the larger fractures and displacements of strata 
are the result of the repetition of such small movements of the 
crust as are taking place now. Admitting that considerable 
areas of the earth’s surface are rising at the rate of a yard or 
more in a century, they yet cannot agree that this is a criterion by 
which to estimate the time required for the elevation of all 
protuberant parts of the earth’s crust. They remind us that in 
our own day we have had experience of paroxysmal changes of 
level, nor can they doubt that similar sudden catastrephes must 
have happened cftentimes in the lapse of ages. They point to 
the appearance of ruin and confusion which may be traced along 
a line of mountain-elevation, and maintain that the broken and 
shattered strata are proofs of a more or less sudden yielding to 
enormous strain ortension. They do not deny that upheaval may 
have been going on over a given area at an extremely slow rate 
during long periods of time, but they argue that a point would 
at last be reached when the tension to which the strata were 
subjected could no longer be resisted. A sudden fracturing 
would at last take place—the strata would be violently dislo- 
cated, thrust forward, crumpled, and heaped, as it were, in 
confused and steeply-inclined masses along the main line of 
dislocation. Again, itis objected to uniformitarian views that 
these do not explain and cannot account for certain remarkable 
mutations of climate which are known to have occurred. It is 
not denied that the earth has been receiving for untold ages the 
same annual amcunt of heat from the sun, but it is maintained 
that, owing to certain astronomical changes, and the modifica- 
tions induced thereby, that heat must have been very differently 
distributed over the globe at various epochs in the past. It is 
held, in short, that the climate both of the northern and the 
southern hemispheres has thus been frequently modified, and 
that in consequence of this the action of the geological agents 
has been influenced again and again—the decay and reconstruc- 
tion of recks the oscillations of the land—and the development 
of floras and faunas having been alternately accelerated and 
retarded according as extreme or moderate conditions prevailed. 
Thus each sehool has its own method of interpreting the 
| fundamental axiom of our science—that the Present is the key to 
the Past. And as the primary aim of geology is to interpret 
the stony record with a view to the reconstruction of our earth’s 
history, itis obviously important that we should be able to satisfy 
ourselves as to which of these rival conceptions is most consonant 
with truth. In other words, we must do our utmost to ascertain 
which givcs the most reasonable interpretation of geological 
phenomena. Each view must in its turn be tested by an appeal 
to facts, and a rigorous application of logicalanalysis. Probably 
we shall find that while there is much to be said on both sides, 
we can agree entirely neither with the one school nor the other. 
Before we are in a position, however, to discuss such questions, 
we must first have ranged over a very wide field of inquiry, and 
obtained a thorough grasp of the principles of our science. 
Meanwhile, our chief concern in beginning our studies must 
necessarily be to detect resemblances between the present and 
the past. For every observation we make we must endeavour 
to discover a correlative phenomenon in the present order of 
things. And so long as we confine our attention to the facts 
before our eyes and to the more obvious interpretations of these 
which are suggested by forces now in action, we shall not fail to 
be impressed with the uniformity of nature. 
We examine, let us suppose, a section of strata exposed upon 
the sea-shore or along the banks of a river. Our knowledge of 
the different kinds of sediment in course of transportation and 
