ANNIVERSARY ADDRESS OF THE PRESIDENT. xi 
tical, faunze and flore in two different localities may be of extremely 
different ages, if the term “age ” is used in its proper chronological 
sense. I stated that “geographical provinces, or zones, may have 
been as distinctly marked in the Paleozoic epoch as at present; and 
those seemingly sudden appearances of new genera and species, which 
we ascribe to new creation, may be simple results of migration.” 
4. The opinion that the oldest known fossils are the earliest forms 
of life has no solid foundation. 
5. If we confine ourselves to positively ascertained facts, the 
total amount of change in the forms of animal and vegetable life 
since the existence of such forms is recorded is small. When com- 
pared with the lapse of time since the first appearance of these 
forms, the amount of change is wonderfully small. Moreover, in 
each great group of the animal and vegetable kingdoms, there are 
certain forms which I termed Prrsistenr Typrs, which have re- 
mained, with but very little apparent change, from their first ap- 
pearance to the present time. 
7. In answer to the question “ What, then, does an impartial 
survey of the positively ascertained truths of palzeontology testify 
in relation to the common doctrines of progressive modification, 
which suppose that modification to have taken place by a necessary 
progress from more to less embryonic forms, from more to less 
generalized types, within the limits of the period represented by 
the fossiliferous rocks?” I reply, “It negatives these doctrines ; 
for it either shows us no evidence of such modification, or demon- 
strates such modification as has occurred to have been very slight ; 
and, as to the nature of that modification, it yields no evidence 
whatsoever that the earlier members of any long-continued group 
were more generalized in structure than the later ones.” 
I think that I cannot employ my last opportunity of addressing 
you, officially, more properly—I may say more dutifully—than in 
revising these old judgments with such help as further knowledge and 
reflection, and an extreme desire to get at the truth, may afford me. 
1. With respect to the first proposition, I may remark that 
whatever may be the case among the physical geologists, catas- 
trophic palzontologists are practically extinct. It is now no part 
of recognized geological doctrine that the species of one formation 
all died out and were replaced by a bran-new set in the next 
formation. On the contrary, it is generally, if not universally, 
agreed that the succession of life has been the result of a slow and 
gradual replacement of species by species; and that all appearances 
of abruptness of change are due to breaks in the series of deposits, 
or other changes in physical conditions. The continuity of living 
forms has been unbroken from the earliest times to the present day. 
2,3. The use of the word “homotaxis” instead of ‘“ synchro- 
nism ” has not, so far as I know, found much favour in the eyes of 
geologists. I hope, therefore, that it is a love for scientific caution, 
and not mere personal affection for a bantling of my own, which 
leads me still to think that the change of phrase is of importance, 
and that the sooner it is made, the sooner shall we get rid of a 
VOL, XXVI. é 
