42 THE PAST CONDITION 



conclusions on and interpretations of the record are 

 really and strictly only valid so long as we confine our- 

 selves to one vertical section. I do not mean to tell 

 you that there are no qualifying circumstances, so 

 that, even in very considerable areas, we may safely 

 speak of conformably superimposed beds being older 

 or younger than others at many different points. But 

 we can never be quite sure in coming to that con- 

 clusion, and especially we cannot be sure if there is 

 any break in their continuity, or any very great dis- 

 tance between the points to be compared. 



"Well now, so much for the record itself, — so much 

 for its imperfections, — so much for the conditions to be 

 observed in interpreting it, and its chronological indi- 

 cations, the moment we pass beyond the limits of a 

 vertical linear section. 



Now let us pass from the record to that which it 

 contains, — from the book itself to the writing and the 

 figures on its pages. This writing and these figures 

 consist of remains of animals and plants which, in the 

 great majority of cases, have lived and died in the very 

 spot in which we now find them, or at least in the im- 

 mediate vicinity. You must all of you be aware — 

 and I referred to the fact in last Monday's lecture — 

 that there are yast numbers of creatures living at the 

 bottom of the sea. These creatures, like all others, 

 sooner or later die, and their shells and hard parts lie 

 at the bottom ; and then the fine mud which is being 

 constantly brought down by rivers and the action of 

 the wear and tear of the sea, covers them over and 

 protects them from any further change or alteration ; 

 and, of course, as in process of time the mud becomes 

 hardened and solidified, the shells of these animals are 



