,,the ,,past ,,condition ,,of ,,organic 
,,nature  ,lecture ,,ii4 7of ,,vi471    
,lectures ,to ,working ,men1 at the     
,museum of ,practical ,geology1 #ahfc1  
,on ,darwin's work3 ,origin of ,species4
   by ,thomas ,h4 ,huxley     ,,in the  
lecture which ,i delivered last ,monday 
evening1 ,i endeavoured to sketch in a  
very brief manner1 but as well as the   
time at my disposal would permit1 the   
present condition of organic nature1    
meaning by that large title simply an   
indication of the great1 broad1 and     
general principles which are to be      
discovered by those who look attentively
 at the phenomena of organic nature as  
at present displayed4 ,the general      
result of our investigations might be   
summed up thus3 we found that the       
multiplicity of the forms of animal     
life1 great as that may be1 may be      
reduced to a comparatively few primitive
 plans or types of construction2 that a 
further study of the development of     
those different forms revealed to us    

that they were again reducible1 until we
 at last brought the infinite diversity 
of animal1 and even vegetable life1 down
 to the primordial form of a single     
cell4  ,we found that our analysis of   
the organic world1 whether animals or   
plants1 showed1 in the long run1 that   
they might both be reduced into1 and    
were1 in fact1 composed of1 the same    
constituents4 ,and we saw that the plant
 obtained the materials constituting its
 substance by a peculiar combination of 
matters belonging entirely to the       
inorganic world2 that1 then1 the animal 
was constantly appropriating the        
nitrogenous matters of the plant to its 
own nourishment1 and returning them back
 to the inorganic world1 in what we     
spoke of as its waste2 and that finally1
 when the animal ceased to exist1 the   
constituents of its body were dissolved 
and transmitted to that inorganic world 
whence they had been at first           
abstracted4 ,thus we saw in both the    
blade of grass and the horse but the    

same elements differently combined and  
arranged4 ,we discovered a continual    
circulation going on1--the plant drawing
 in the elements of inorganic nature and
 combining them into food for the animal
 creation2 the animal borrowing from the
 plant the matter for its own support1  
giving off during its life products     
which returned immediately to the       
inorganic world2 and that1 eventually1  
the constituent materials of the whole  
structure of both animals and plants    
were thus returned to their original    
source3 there was a constant passage    
from one state of existence to another1 
and a returning back again4  ,lastly1   
when we endeavoured to form some notion 
of the nature of the forces exercised by
 living beings1 we discovered that      
they--if not capable of being subjected 
to the same minute analysis as the      
constituents of those beings            
themselves--that they were correlative  
with--that they were the equivalents of 
the forces of inorganic nature--that    

they were1 in the sense in which the    
term is now used1 convertible with them4
 ,that was our general result4  ,and    
now1 leaving the ,present1 ,i must      
endeavour in the same manner to put     
before you the facts that are to be     
discovered in the ,past history of the  
living world1 in the past conditions of 
organic nature4 ,we have1 to-night1 to  
deal with the facts of that history--a  
history involving periods of time before
 which our mere human records sink into 
utter insignificance--a history the     
variety and physical magnitude of whose 
events cannot even be foreshadowed by   
the history of human life and human     
phenomena--a history of the most varied 
and complex character4  ,we must deal   
with the history1 then1 in the first    
place1 as we should deal with all other 
histories4 ,the historical student knows
 that his first business should be to   
inquire into the validity of his        
evidence1 and the nature of the record  
in which the evidence is contained1 that

 he may be able to form a proper        
estimate of the correctness of the      
conclusions which have been drawn from  
that evidence4 ,so1 here1 we must pass1 
in the first place1 to the consideration
 of a matter which may seem foreign to  
the question under discussion4 ,we must 
dwell upon the nature of the records1   
and the credibility of the evidence they
 contain2 we must look to the           
completeness or incompleteness of those 
records themselves1 before we turn to   
that which they contain and reveal4 ,the
 question of the credibility of the     
history1 happily for us1 will not       
require much consideration1 for1 in this
 history1 unlike those of human origin1 
there can be no cavilling1 no           
differences as to the reality and truth 
of the facts of which it is made up2 the
 facts state themselves1 and are laid   
out clearly before us4  ,but1 although  
one of the greatest difficulties of the 
historical student is cleared out of our
 path1 there are other                  

difficulties--difficulties in rightly   
interpreting the facts as they are      
presented to us--which may be compared  
with the greatest difficulties of any   
other kinds of historical study4  ,what 
is this record of the past history of   
the globe1 and what are the questions   
which are involved in an inquiry into   
its completeness or incompleteness8     
,that record is composed of mud2 and the
 question which we have to investigate  
this evening resolves itself into a     
question of the formation of mud4 ,you  
may think1 perhaps1 that this is a vast 
step--of almost from the sublime to the 
ridiculous--from the contemplation of   
the history of the past ages of the     
world's existence to the consideration  
of the history of the formation of mud6 
,but1 in nature1 there is nothing mean  
and unworthy of attention2 there is     
nothing ridiculous or contemptible in   
any of her works2 and this inquiry1 you 
will soon see1 ,i hope1 takes us to the 
very root and foundations of our        

subject4  ,how1 then1 is mud formed8    
,always1 with some trifling exception1  
which ,i need not consider now--always1 
as the result of the action of water1   
wearing down and disintegrating the     
surface of the earth and rocks with     
which it comes in contact--pounding and 
grinding it down1 and carrying the      
particles away to places where they     
cease to be disturbed by this mechanical
 action1 and where they can subside and 
rest4 ,for the ocean1 urged by winds1   
washes1 as we know1 a long extent of    
coast1 and every wave1 loaded as it is  
with particles of sand and gravel as it 
breaks upon the shore1 does something   
towards the disintegrating process4 ,and
 thus1 slowly but surely1 the hardest   
rocks are gradually ground down to a    
powdery substance2 and the mud thus     
formed1 coarser or finer1 as the case   
may be1 is carried by the rush of the   
tides1 or currents1 till it reaches the 
comparatively deeper parts of the ocean1
 in which it can sink to the bottom1    

that is1 to parts where there is a depth
 of about fourteen or fifteen fathoms1 a
 depth at which the water is1 usually1  
nearly motionless1 and in which1 of     
course1 the finer particles of this     
detritus1 or mud as we call it1 sinks to
 the bottom4  ,or1 again1 if you take a 
river1 rushing down from its mountain   
sources1 brawling over the stones and   
rocks that intersect its path1          
loosening1 removing1 and carrying with  
it in its downward course the pebbles   
and lighter matters from its banks1 it  
crushes and pounds down the rocks and   
earths in precisely the same way as the 
wearing action of the sea waves4 ,the   
matters forming the deposit are torn    
from the mountain-side and whirled      
impetuously into the valley1 more slowly
 over the plain1 thence into the        
estuary1 and from the estuary they are  
swept into the sea4 ,the coarser and    
heavier fragments are obviously         
deposited first1 that is1 as soon as the
 current begins to lose its force by    

becoming amalgamated with the stiller   
depths of the ocean1 but the finer and  
lighter particles are carried further   
on1 and eventually deposited in a deeper
 and stiller portion of the ocean4  ,it 
clearly follows from this that mud gives
 us a chronology2 for it is evident that
 supposing this1 which ,i now sketch1 to
 be the sea bottom1 and supposing this  
to be a coast-line2 from the washing    
action of the sea upon the rock1 wearing
 and grinding it down into a sediment of
 mud1 the mud will be carried down1 and 
at length1 deposited in the deeper parts
 of this sea bottom1 where it will form 
a layer2 and then1 while that first     
layer is hardening1 other mud which is  
coming from the same source will1 of    
course1 be carried to the same place2   
and1 as it is quite impossible for it to
 get beneath the layer already there1 it
 deposits itself above it1 and forms    
another layer1 and in that way you      
gradually have layers of mud constantly 
forming and hardening one above the     

other1 and conveying a record of time4  
,it is a necessary result of the        
operation of the law of gravitation that
 the uppermost layer shall be the       
youngest and the lowest the oldest1 and 
that the different beds shall be older  
at any particular point or spot in      
exactly the ratio of their depth from   
the surface4 ,so that if they were      
upheaved afterwards1 and you had a      
series of these different layers of mud1
 converted into sandstone1 or limestone1
 as the case might be1 you might be sure
 that the bottom layer was deposited    
first1 and that the upper layers were   
formed afterwards4 ,here1 you see1 is   
the first step in the history--these    
layers of mud give us an idea of time4  
,the whole surface of the earth1--,i    
speak broadly1 and leave out minor      
qualifications1--is made up of such     
layers of mud1 so hard1 the majority of 
them1 that we call them rock whether    
limestone or sandstone1 or other        
varieties of rock4 ,and1 seeing that    

every part of the crust of the earth is 
made up in this way1 you might think    
that the determination of the           
chronology1 the fixing of the time which
 it has taken to form this crust is a   
comparatively simple matter4 ,take a    
broad average1 ascertain how fast the   
mud is deposited upon the bottom of the 
sea1 or in the estuary of rivers2 take  
it to be an inch1 or two1 or three      
inches a year1 or whatever you may      
roughly estimate it at2 then take the   
total thickness of the whole series of  
stratified rocks1 which geologists      
estimate at twelve or thirteen miles1 or
 about seventy thousand feet1 make a sum
 in short division1 divide the total    
thickness by that of the quantity       
deposited in one year1 and the result   
will1 of course1 give you the number of 
years which the crust has taken to form4
  ,truly1 that looks a very simple      
process6 ,it would be so except for     
certain difficulties1 the very first of 
which is that of finding how rapidly    

sediments are deposited2 but the main   
difficulty--a difficulty which renders  
any certain calculations of such a      
matter out of the question--is this1 the
 sea-bottom on which the deposit takes  
place is continually shifting4  ,instead
 of the surface of the earth being that 
stable1 fixed thing that it is popularly
 believed to be1 being1 in common       
parlance1 the very emblem of fixity     
itself1 it is incessantly moving1 and   
is1 in fact1 as unstable as the surface 
of the sea1 except that its undulations 
are infinitely slower and enormously    
higher and deeper4  ,now1 what is the   
effect of this oscillation8 ,take the   
case to which ,i have previously        
referred4 ,the finer or coarser         
sediments that are carried down by the  
current of the river1 will only be      
carried out a certain distance1 and     
eventually1 as we have already seen1 on 
reaching the stiller part of the ocean1 
will be deposited at the bottom4  ,let  
,c y 7,fig4 #d7 be the sea-bottom1 y ,d 

the shore1 x y the sea-level1 then the  
coarser deposit will subside over the   
region ,b1 the finer over ,a1 while     
beyond ,a there will be no deposit at   
all2 and1 consequently1 no record will  
be kept1 simply because no deposit is   
going on4 ,now1 suppose that the whole  
land1 ,c1 ,d1 which we have regarded as 
stationary1 goes down1 as it does so1   
both ,a and ,b go further out from the  
shore1 which will be at y#a2 x#a1 y#a1  
being the new sea-level4 ,the           
consequence will be that the layer of   
mud 7,a71 being now1 for the most part1 
further than the force of the current is
 strong enough to convey even the finest
 'debris'1 will1 of course1 receive no  
more deposits1 and having attained a    
certain thickness will now grow no      
thicker4  ,we should be misled in taking
 the thickness of that layer1 whenever  
it may be exposed to our view1 as a     
record of time in the manner in which we
 are now regarding this subject1 as it  
would give us only an imperfect and     

partial record3 it would seem to        
represent too short a period of time4   
,illustration3 ,fig4#d4  ,suppose1 on   
the other hand1 that the land 7,c ,d7   
had gone on rising slowly and           
gradually--say an inch or two inches in 
the course of a century1--what would be 
the practical effect of that movement8  
,why1 that the sediment ,a and ,b which 
has been already deposited1 would       
eventually be brought nearer to the     
shore-level1 and again subjected to the 
wear and tear of the sea2 and directly  
the sea begins to act upon it1 it would 
of course soon cut up and carry it away1
 to a greater or less extent1 to be     
re-deposited further out4  ,well1 as    
there is1 in all probability1 not one   
single spot on the whole surface of the 
earth1 which has not been up and down in
 this way a great many times1 it follows
 that the thickness of the deposits     
formed at any particular spot cannot be 
taken 7even supposing we had at first   
obtained correct data as to the rate at 

which they took place7 as affording     
reliable information as to the period of
 time occupied in its deposit4 ,so that 
you see it is absolutely necessary from 
these facts1 seeing that our record     
entirely consists of accumulations of   
mud1 superimposed one on the other2     
seeing in the next place that any       
particular spots on which accumulations 
have occurred1 have been constantly     
moving up and down1 and sometimes out of
 the reach of a deposit1 and at other   
times its own deposit broken up and     
carried away1 it follows that our record
 must be in the highest degree          
imperfect1 and we have hardly a trace   
left of thick deposits1 or any definite 
knowledge of the area that they         
occupied1 in a great many cases4 ,and   
mark this6 ,that supposing even that the
 whole surface of the earth had been    
accessible to the geologist1--that man  
had had access to every part of the     
earth1 and had made sections of the     
whole1 and put them all together1--even 

then his record must of necessity be    
imperfect4  ,but to how much has man    
really access8 ,if you will look at this
 ,map you will see that it represents   
the proportion of the sea to the earth3 
this coloured part indicates all the dry
 land1 and this other portion is the    
water4 ,you will notice at once that the
 water covers three-fifths of the whole 
surface of the globe1 and has covered it
 in the same manner ever since man has  
kept any record of his own observations1
 to say nothing of the minute period    
during which he has cultivated          
geological inquiry4 ,so that            
three-fifths of the surface of the earth
 is shut out from us because it is under
 the sea4 ,let us look at the other     
two-fifths1 and see what are the        
countries in which anything that may be 
termed searching geological inquiry has 
been carried out3 a good deal of        
,france1 ,germany1 and ,great ,britain  
and ,ireland1 bits of ,spain1 of ,italy1
 and of ,russia1 have been examined1 but

 of the whole great mass of ,africa1    
except parts of the southern extremity1 
we know next to nothing2 little bits of 
,india1 but of the greater part of the  
,asiatic continent nothing2 bits of the 
,northern ,american ,states and of      
,canada1 but of the greater part of the 
continent of ,north ,america1 and in    
still larger proportion1 of ,south      
,america1 nothing6  ,under these        
circumstances1 it follows that even with
 reference to that kind of imperfect    
information which we can possess1 it is 
only of about the ten-thousandth part of
 the accessible parts of the earth that 
has been examined properly4 ,therefore1 
it is with justice that the most        
thoughtful of those who are concerned in
 these inquiries insist continually upon
 the imperfection of the geological     
record2 for1 ,i repeat1 it is absolutely
 necessary1 from the nature of things1  
that that record should be of the most  
fragmentary and imperfect character4    
,unfortunately this circumstance has    

been constantly forgotten4 ,men of      
science1 like young colts in a fresh    
pasture1 are apt to be exhilarated on   
being turned into a new field of        
inquiry1 to go off at a hand-gallop1 in 
total disregard of hedges and ditches1  
losing sight of the real limitation of  
their inquiries1 and to forget the      
extreme imperfection of what is really  
known4 ,geologists have imagined that   
they could tell us what was going on at 
all parts of the earth's surface during 
a given epoch2 they have talked of this 
deposit being contemporaneous with that 
deposit1 until1 from our little local   
histories of the changes at limited     
spots of the earth's surface1 they have 
constructed a universal history of the  
globe as full of wonders and portents as
 any other story of antiquity4  ,but    
what does this attempt to construct a   
universal history of the globe imply8   
,it implies that we shall not only have 
a precise knowledge of the events which 
have occurred at any particular point1  

but that we shall be able to say what   
events1 at any one spot1 took place at  
the same time with those at other spots4
  ,let us see how far that is in the    
nature of things practicable4 ,suppose  
that here ,i make a section of the ,lake
 of ,killarney1 and here the section of 
another lake--that of ,loch ,lomond in  
,scotland for instance4 ,the rivers that
 flow into them are constantly carrying 
down deposits of mud1 and beds1 or      
strata1 are being as constantly formed1 
one above the other1 at the bottom of   
those lakes4 ,now1 there is not a shadow
 of doubt that in these two lakes the   
lower beds are all older than the       
upper--there is no doubt about that2 but
 what does 'this' tell us about the age 
of any given bed in ,loch ,lomond1 as   
compared with that of any given bed in  
the ,lake of ,killarney8 ,it is1 indeed1
 obvious that if any two sets of        
deposits are separated and              
discontinuous1 there is absolutely no   
means whatever given you by the nature  

of the deposit of saying whether one is 
much younger or older than the other2   
but you may say1 as many have said and  
think1 that the case is very much       
altered if the beds which we are        
comparing are continuous4 ,suppose two  
beds of mud hardened into rock1--,a and 
,b-are seen in section4 7,fig4 #e47     
,illustration3 ,fig4 #e4  ,well1 you    
say1 it is admitted that the lowermost  
bed is always the older4 ,very well2 ,b1
 therefore1 is older than ,a4 ,no doubt1
 'as a whole'1 it is so2 or if any parts
 of the two beds which are in the same  
vertical line are compared1 it is so4   
,but suppose you take what seems a very 
natural step further1 and say that the  
part 'a' of the bed ,a is younger than  
the part 'b' of the bed ,b4 ,is this    
sound reasoning8 ,if you find any record
 of changes taking place at 'b'1 did    
they occur before any events which took 
place while 'a' was being deposited8 ,it
 looks all very plain sailing1 indeed1  
to say that they did2 and yet there is  

no proof of anything of the kind4 ,as   
the former ,director of this            
,institution1 ,sir ,h4 ,de la ,beche1   
long ago showed1 this reasoning may     
involve an entire fallacy4 ,it is       
extremely possible that 'a' may have    
been deposited ages before 'b'4 ,it is  
very easy to understand how that can be4
 ,to return to ,fig4 #d2 when ,a and ,b 
were deposited1 they were               
'substantially' contemporaneous2 ,a     
being simply the finer deposit1 and ,b  
the coarser of the same detritus or     
waste of land4 ,now suppose that that   
sea-bottom goes down 7as shown in ,fig4 
#d71 so that the first deposit is       
carried no farther than 'a'1 forming the
 bed ,al1 and the coarse no farther than
 'b'1 forming the bed ,b#a1 the result  
will be the formation of two continuous 
beds1 one of fine sediment 7,a ,a#a7    
over-lapping another of coarse sediment 
7,b ,b#a74 ,now suppose the whole       
sea-bottom is raised up1 and a section  
exposed about the point ,al2 no doubt1  

'at this spot'1 the upper bed is younger
 than the lower4 ,but we should         
obviously greatly err if we concluded   
that the mass of the upper bed at ,a was
 younger than the lower bed at ,b2 for  
we have just seen that they are         
contemporaneous deposits4 ,still more   
should we be in error if we supposed the
 upper bed at ,a to be younger than the 
continuation of the lower bed at ,bl2   
for ,a was deposited long before ,b#a4  
,in fine1 if1 instead of comparing      
immediately adjacent parts of two beds1 
one of which lies upon another1 we      
compare distant parts1 it is quite      
possible that the upper may be any      
number of years older than the under1   
and the under any number of years       
younger than the upper4  ,now you must  
not suppose that ,i put this before you 
for the purpose of raising a paradoxical
 difficulty2 the fact is1 that the great
 mass of deposits have taken place in   
sea-bottoms which are gradually sinking1
 and have been formed under the very    

conditions ,i am here supposing4  ,do   
not run away with the notion that this  
subverts the principle ,i laid down at  
first4 ,the error lies in extending a   
principle which is perfectly applicable 
to deposits in the same vertical line to
 deposits which are not in that relation
 to one another4  ,it is in consequence 
of circumstances of this kind1 and of   
others that ,i might mention to you1    
that our conclusions on and             
interpretations of the record are really
 and strictly only valid so long as we  
confine ourselves to one vertical       
section4 ,i do not mean to tell you that
 there are no qualifying circumstances1 
so that1 even in very considerable      
areas1 we may safely speak of           
conformably superimposed beds being     
older or younger than others at many    
different points4 ,but we can never be  
quite sure in coming to that conclusion1
 and especially we cannot be sure if    
there is any break in their continuity1 
or any very great distance between the  

points to be compared4  ,well now1 so   
much for the record itself1--so much for
 its imperfections1--so much for the    
conditions to be observed in            
interpreting it1 and its chronological  
indications1 the moment we pass beyond  
the limits of a vertical linear section4
  ,now let us pass from the record to   
that which it contains1--from the book  
itself to the writing and the figures on
 its pages4 ,this writing and these     
figures consist of remains of animals   
and plants which1 in the great majority 
of cases1 have lived and died in the    
very spot in which we now find them1 or 
at least in the immediate vicinity4 ,you
 must all of you be aware--and ,i       
referred to the fact in my last         
lecture--that there are vast numbers of 
creatures living at the bottom of the   
sea4 ,these creatures1 like all others1 
sooner or later die1 and their shells   
and hard parts lie at the bottom2 and   
then the fine mud which is being        
constantly brought down by rivers and   

the action of the wear and tear of the  
sea1 covers them over and protects them 
from any further change or alteration2  
and1 of course1 as in process of time   
the mud becomes hardened and solidified1
 the shells of these animals are        
preserved and firmly imbedded in the    
limestone or sandstone which is being   
thus formed4 ,you may see in the        
galleries of the ,museum up stairs      
specimens of limestones in which such   
fossil remains of existing animals are  
imbedded4 ,there are some specimens in  
which turtles' eggs have been imbedded  
in calcareous sand1 and before the sun  
had hatched the young turtles1 they     
became covered over with calcareous mud1
 and thus have been preserved and       
fossilized4  ,not only does this process
 of imbedding and fossilization occur   
with marine and other aquatic animals   
and plants1 but it affects those land   
animals and plants which are drifted    
away to sea1 or become buried in bogs or
 morasses2 and the animals which have   

been trodden down by their fellows and  
crushed in the mud at the river's bank1 
as the herd have come to drink4 ,in any 
of these cases1 the organisms may be    
crushed or be mutilated1 before or after
 putrefaction1 in such a manner that    
perhaps only a part will be left in the 
form in which it reaches us4 ,it is1    
indeed1 a most remarkable fact1 that it 
is quite an exceptional case to find a  
skeleton of any one of all the thousands
 of wild land animals that we know are  
constantly being killed1 or dying in the
 course of nature3 they are preyed on   
and devoured by other animals or die in 
places where their bodies are not       
afterwards protected by mud4 ,there are 
other animals existing in the sea1 the  
shells of which form exceedingly large  
deposits4 ,you are probably aware that  
before the attempt was made to lay the  
,atlantic telegraphic cable1 the        
,government employed vessels in making a
 series of very careful observations and
 soundings of the bottom of the         

,atlantic2 and although1 as we must all 
regret1 up to the present time that     
project has not succeeded1 we have the  
satisfaction of knowing that it yielded 
some most remarkable results to science4
 ,the ,atlantic ,ocean had to be sounded
 right across1 to depths of several     
miles in some places1 and the nature of 
its bottom was carefully ascertained4   
,well1 now1 a space of about #a1jjj     
miles wide from east to west1 and ,i do 
not exactly know how many from north to 
south1 but at any rate #fjj or #gjj     
miles1 was carefully examined1 and it   
was found that over the whole of that   
immense area an excessively fine chalky 
mud is being deposited2 and this deposit
 is entirely made up of animals whose   
hard parts are deposited in this part of
 the ocean1 and are doubtless gradually 
acquiring solidity and becoming         
metamorphosed into a chalky limestone4  
,thus1 you see1 it is quite possible in 
this way to preserve unmistakable       
records of animal and vegetable life4   

,whenever the sea-bottom1 by some of    
those undulations of the earth's crust  
that ,i have referred to1 becomes       
upheaved1 and sections or borings are   
made1 or pits are dug1 then we become   
able to examine the contents and        
constituents of these ancient           
sea-bottoms1 and find out what manner of
 animals lived at that period4  ,now it 
is a very important consideration in its
 bearing on the completeness of the     
record1 to inquire how far the remains  
contained in these fossiliferous        
limestones are able to convey anything  
like an accurate or complete account of 
the animals which were in existence at  
the time of its formation4 ,upon that   
point we can form a very clear judgment1
 and one in which there is no possible  
room for any mistake4 ,there are of     
course a great number of animals--such  
as jelly-fishes1 and other              
animals--without any hard parts1 of     
which we cannot reasonably expect to    
find any traces whatever3 there is      

nothing of them to preserve4 ,within a  
very short time1 you will have noticed1 
after they are removed from the water1  
they dry up to a mere nothing2 certainly
 they are not of a nature to leave any  
very visible traces of their existence  
on such bodies as chalk or mud4 ,then   
again1 look at land animals2 it is1 as  
,i have said1 a very uncommon thing to  
find a land animal entire after death4  
,insects and other carnivorous animals  
very speedily pull them to pieces1      
putrefaction takes place1 and so1 out of
 the hundreds of thousands that are     
known to die every year1 it is the      
rarest thing in the world to see one    
imbedded in such a way that its remains 
would be preserved for a lengthened     
period4 ,not only is this the case1 but 
even when animal remains have been      
safely imbedded1 certain natural agents 
may wholly destroy and remove them4     
,almost all the hard parts of           
animals--the bones and so on--are       
composed chiefly of phosphate of lime   

and carbonate of lime4 ,some years ago1 
,i had to make an inquiry into the      
nature of some very curious fossils sent
 to me from the ,north of ,scotland4    
,fossils are usually hard bony          
structures that have become imbedded in 
the way ,i have described1 and have     
gradually acquired the nature and       
solidity of the body with which they are
 associated2 but in this case ,i had a  
series of 'holes' in some pieces of     
rock1 and nothing else4 ,those holes1   
however1 had a certain definite shape   
about them1 and when ,i got a skilful   
workman to make castings of the interior
 of these holes1 ,i found that they were
 the impressions of the joints of a     
backbone and of the armour of a great   
reptile1 twelve or more feet long4 ,this
 great beast had died and got buried in 
the sand2 the sand had gradually        
hardened over the bones1 but remained   
porous4 ,water had trickled through it1 
and that water being probably charged   
with a superfluity of carbonic acid1 had

 dissolved all the phosphate and        
carbonate of lime1 and the bones        
themselves had thus decayed and entirely
 disappeared2 but as the sandstone      
happened to have consolidated by that   
time1 the precise shape of the bones was
 retained4 ,if that sandstone had       
remained soft a little longer1 we should
 have known nothing whatsoever of the   
existence of the reptile whose bones it 
had encased4  ,how certain it is that a 
vast number of animals which have       
existed at one period on this earth have
 entirely perished1 and left no trace   
whatever of their forms1 may be proved  
to you by other considerations4 ,there  
are large tracts of sandstone in various
 parts of the world1 in which nobody has
 yet found anything but footsteps4 ,not 
a bone of any description1 but an       
enormous number of traces of footsteps4 
,there is no question about them4 ,there
 is a whole valley in ,connecticut      
covered with these footsteps1 and not a 
single fragment of the animals which    

made them has yet been found4 ,let me   
mention another case while upon that    
matter1 which is even more surprising   
than those to which ,i have yet         
referred4 ,there is a limestone         
formation near ,oxford1 at a place      
called ,stonesfield1 which has yielded  
the remains of certain very interesting 
mammalian animals1 and up to this time1 
if ,i recollect rightly1 there have been
 found seven specimens of its lower     
jaws1 and not a bit of anything else1   
neither limb-bones nor skull1 or any    
part whatever2 not a fragment of the    
whole system6 ,of course1 it would be   
preposterous to imagine that the beasts 
had nothing else but a lower jaw6 ,the  
probability is1 as ,dr4 ,buckland       
showed1 as the result of his            
observations on dead dogs in the river  
,thames1 that the lower jaw1 not being  
secured by very firm ligaments to the   
bones of the head1 and being a weighty  
affair1 would easily be knocked off1 or 
might drop away from the body as it     

floated in water in a state of          
decomposition4 ,the jaw would thus be   
deposited immediately1 while the rest of
 the body would float and drift away    
altogether1 ultimately reaching the sea1
 and perhaps becoming destroyed4 ,the   
jaw becomes covered up and preserved in 
the river silt1 and thus it comes that  
we have such a curious circumstance as  
that of the lower jaws in the           
,stonesfield slates4 ,so that1 you see1 
faulty as these layers of stone in the  
earth's crust are1 defective as they    
necessarily are as a record1 the account
 of contemporaneous vital phenomena     
presented by them is1 by the necessity  
of the case1 infinitely more defective  
and fragmentary4  ,it was necessary that
 ,i should put all this very strongly   
before you1 because1 otherwise1 you     
might have been led to think differently
 of the completeness of our knowledge by
 the next facts ,i shall state to you4  
,the researches of the last             
three-quarters of a century have1 in    

truth1 revealed a wonderful richness of 
organic life in those rocks4 ,certainly 
not fewer than thirty or forty thousand 
different species of fossils have been  
discovered4 ,you have no more ground for
 doubting that these creatures really   
lived and died at or near the places in 
which we find them than you have for    
like scepticism about a shell on the    
sea-shore4 ,the evidence is as good in  
the one case as in the other4  ,our next
 business is to look at the general     
character of these fossil remains1 and  
it is a subject which it will be        
requisite to consider carefully2 and the
 first point for us is to examine how   
much the extinct ',flora' and ',fauna'  
as a 'whole'--disregarding altogether   
the 'succession' of their constituents1 
of which ,i shall speak                 
afterwards--differ from the ',flora' and
 ',fauna' of the present day2--how far  
they differ in what we 'do' know about  
them1 leaving altogether out of         
consideration speculations based upon   

what we 'do not' know4  ,i strongly     
imagine that if it were not for the     
peculiar appearance that fossilised     
animals have1 any of you might readily  
walk through a museum which contains    
fossil remains mixed up with those of   
the present forms of life1 and ,i doubt 
very much whether your uninstructed eyes
 would lead you to see any vast or      
wonderful difference between the two4   
,if you looked closely1 you would       
notice1 in the first place1 a great many
 things very like animals with which you
 are acquainted now3 you would see      
differences of shape and proportion1 but
 on the whole a close similarity4  ,i   
explained what ,i meant by ,,orders the 
other day1 when ,i described the animal 
kingdom as being divided in             
sub-kingdoms1 classes and orders4 ,if   
you divide the animal kingdom into      
orders1 you will find that there are    
about one hundred and twenty4 ,the      
number may vary on one side or the      
other1 but this is a fair estimate4     

,that is the sum total of the orders of 
all the animals which we know now1 and  
which have been known in past times1 and
 left remains behind4  ,now1 how many of
 those are absolutely extinct8 ,that is 
to say1 how many of these orders of     
animals have lived at a former period of
 the world's history1 but have at       
present no representatives8 ,that is the
 sense in which ,i meant to use the word
 extinct4 ,i mean that those animals did
 live on this earth at one time1 but    
have left no one of their kind with us  
at the present moment4 ,so that         
estimating the number of extinct animals
 is a sort of way of comparing the past 
creation as a whole with the present as 
a whole4 ,among the mammalia and birds  
there are none extinct2 but when we come
 to the reptiles there is a most        
wonderful thing3 out of the eight       
orders1 or thereabouts1 which you can   
make among reptiles1 one-half are       
extinct4 ,these diagrams of the         
plesiosaurus1 the ichthyosaurus1 the    

pterodactyle1 give you a notion of some 
of these extinct reptiles4 ,and here is 
a cast of the pterodactyle and bones of 
the ichthyosaurus and the plesiosaurus1 
just as fresh as if it had been recently
 dug up in a churchyard4 ,thus1 in the  
reptile class1 there are no less than   
half of the orders which are absolutely 
extinct4 ,if we turn to the ',amphibia'1
 there was one extinct order1 the       
,labyrinthodonts1 typified by the large 
salamander-like beast shown in this     
diagram4  ,no order of fishes is known  
to be extinct4 ,every fish that we find 
in the strata--to which ,i have been    
referring--can be identified and placed 
in one of the orders which exist at the 
present day4 ,there is not known to be a
 single ordinal form of insect extinct4 
,there are only two orders extinct among
 the ',crustacea'4 ,there is not known  
to be an extinct order of these         
creatures1 the parasitic and other      
worms2 but there are two1 not to say    
three1 absolutely extinct orders of this

 class1 the ',echinodermata'2 out of all
 the orders of the ',coelenterata' and  
',protozoa' only one1 the ,rugose       
,corals4  ,so that1 you see1 out of     
somewhere about #abj orders of animals1 
taking them altogether1 you will not1 at
 the outside estimate1 find above ten or
 a dozen extinct4 ,summing up all the   
orders of animals which have left       
remains behind them1 you will not find  
above ten or a dozen which cannot be    
arranged with those of the present day2 
that is to say1 that the difference does
 not amount to much more than ten per   
cent43 and the proportion of extinct    
orders of plants is still smaller4 ,i   
think that that is a very astounding1 a 
most astonishing fact1 seeing the       
enormous epochs of time which have      
elapsed during the constitution of the  
surface of the earth as it at present   
exists2 it is1 indeed1 a most astounding
 thing that the proportion of extinct   
ordinal types should be so exceedingly  
small4  ,but now1 there is another point

 of view in which we must look at this  
past creation4 ,suppose that we were to 
sink a vertical pit through the floor   
beneath us1 and that ,i could succeed in
 making a section right through in the  
direction of ,new ,zealand1 ,i should   
find in each of the different beds      
through which ,i passed the remains of  
animals which ,i should find in that    
stratum and not in the others4 ,first1  
,i should come upon beds of gravel or   
drift containing the bones of large     
animals1 such as the elephant1          
rhinoceros1 and cave tiger4 ,rather     
curious things to fall across in        
,piccadilly6 ,if ,i should dig lower    
still1 ,i should come upon a bed of what
 we call the ,london clay1 and in this1 
as you will see in our galleries        
upstairs1 are found remains of strange  
cattle1 remains of turtles1 palms1 and  
large tropical fruits2 with shell-fish  
such as you see the like of now only in 
tropical regions4 ,if ,i went below     
that1 ,i should come upon the chalk1 and

 there ,i should find something         
altogether different1 the remains of    
ichthyosauri and pterodactyles1 and     
ammonites1 and so forth4  ,i do not know
 what ,mr4 ,godwin ,austin would say    
comes next1 but probably rocks          
containing more ammonites1 and more     
ichthyosauri and plesiosauri1 with a    
vast number of other things2 and under  
that ,i should meet with yet older      
rocks1 containing numbers of strange    
shells and fishes2 and in thus passing  
from the surface to the lowest depths of
 the earth's crust1 the forms of animal 
life and vegetable life which ,i should 
meet with in the successive beds would1 
looking at them broadly1 be the more    
different the further that ,i went down4
 ,or1 in other words1 inasmuch as we    
started with the clear principle1 that  
in a series of naturally-disposed mud   
beds the lowest are the oldest1 we      
should come to this result1 that the    
further we go back in time the more     
difference exists between the animal and

 vegetable life of an epoch and that    
which now exists4 ,that was the         
conclusion to which ,i wished to bring  
you at the end of this ,lecture4