ANNIVERSARY ADDRESS OF THE PRESIDENT. Ixvii 



envelope of a particular individual, vre ought to find a greater irre- 

 gularity in their development in the same shell, and asks why, if this 

 theory were true, should the heights of different coils of the same 

 spiral present constant relations, and why the first and last cells 

 should be less large than those of the median whorls, we cannot 

 accept the objections, for a crowd of compai'able phsenomena pre- 

 sented by the Sertularian zoophytes, animals having considerable 

 aifinity with the Polyzoa, although of higher organization, come to 

 our recollection. The variations of the Hydroida, their morpho- 

 logy and reproduction, bear too^ close a relation to the phsenomena 

 exhibited by the rhizopodous organism, to permit us to regard the 

 Nummulite and its allies as simple bodies, or to dispute the theory 

 of their gemmigerous constitution ; in other words, the regulation of 

 their organization by the law of paramorphosis. 



The stratigraphical distribution of the Nummulites is especially of 

 interest to the geologist. As compared with the grand scale of 

 epochs, their reign was short, but it was well-marked and compact, 

 and offers but one more proof to the thousands now known towards 

 the demonstration of the unity of time-areas of natural genera, facts 

 that should make us strongly hesitate before admitting the value of 

 apparent and daily-decreasing exceptions, and that should give us fresh 

 hope of the future attainment of a knowledge of the grand laws re- 

 gulating life in its relations to time, and fresh faith in the biological 

 section of the foundations of geology. The Nummulites characterize 

 a portion, not the whole, of the tertiary epoch. Though once, and 

 not many years ago, Nummulites were regarded to be as probably in- 

 dicative of the cretaceous date of a formation as of its tertiary place, 

 it would now appear that, between the nummulitic tertiaries and true 

 cretaceous strata, deposits intervene, whose fauna and flora are such 

 that we must regard them as of tertiary age. A most interesting and 

 important feature of these deposits, traceable in the north-west of 

 Europe, the south of France, in Savoy, in Switzerland, along the 

 southern slopes of the Alps, in Istria, and even in India, is, that in 

 numerous localities they exhibit evidences of a terrestrial origin, 

 marked by the presence of coal, often accompanied by lacustrine shells, 

 and sometimes by freshwater limestones. In facts of this kind we 

 may get at the true explanation of the break between the cretaceous 

 and tertiary faunas, vdthout having recourse to prodigious cataclysms 

 or paroxysmal elevations of mountain chains, which, if they did 

 occur, as might have been the case, could have made far less im- 

 pression on the distribution of animal and vegetable life, except in 

 the immediate vicinity of the convulsion, than slow and almost 

 imperceptible changes affecting gradually the disposition of the geo- 

 graphy of a wide-spread area. 



" The dial moves, and yet it is not seen," paradoxically writes an 

 old poet. Time cannot progress without change, however slow may 

 seem his course. The true measure of the extent and importance of 

 a convulsion (as well as of the importance of unconformity), should 

 be the amount of organic change that we can trace to a connexion 



