ANNIVERSARY ADDRESS OF THE PRESIDENT. 75 



horizons in these countries are certainly, for the most part, not 

 identical but only representative. JSTo fact, it seems to me, could 

 more clearly indicate that, even at that early period, there were life- 

 provinces with a distribution of organisms in space quite analogous 

 to that which exists at the present day. 



To pass to slightly younger rocks. What can be more striking 

 than the evidence of the juxtaposition of two life-provinces, afforded 

 by the Calciferous strata of North America and the similar rocks of 

 Scotland and Northern Europe, which contain the remarkable 

 Ilaclurece, a peculiar assemblage of Cephalopods, and other fossils ? 

 for these are seen at Girvan to come into close contiguity with the 

 more southern type of Silurian, containing a very different fauna, so 

 well exhibited in the Lake-district and in North Wales. 



Another striking example of the same kind is afforded by the 

 Cretaceous, of which the Southern type, marked by the abundance 

 of Hippurites^ Orbitolites, and other remarkable forms, comes into 

 close relations, as has been so well shown by Hebert, with the type 

 which yields the ordinary Cretaceous fauna of Central Europe. In 

 these and similar cases which might be mentioned we trace the 

 existence of two approximating marine provinces, like those which 

 at the present day are separated by the Isthmus of Panama. 



Professors Neumayr and Mojsisovics have indeed shown that 

 there are good causes for believing that the distinction between the 

 marine zoological provinces in Triassic and Jurassic times was at 

 least as clearly marked as between the similar provinces of the 

 present day ; and the former naturalist has in addition pointed out 

 that within the geographical provinces we have also very recognizable 

 climatic zones. 



In the year 1862, Professor Huxley, speaking from this Chair, 

 uttered a much needed warning against the growing practice 

 among palaeontologists of treating Geological equivalence as meaning 

 the same as actual contemporaneity ; and against the assumption, 

 without positive proof, that ancient faunas and floras had au 

 indefinite and even world-wide distribution. Palseontological dis- 

 coveries during the last quarter of a century in Western North 

 America, in India, in the Cape Colony, Australia, and New Zealand 

 have abundantly justified these cautions, and have shown how 

 much such a term as *' homotaxis " is needed, in order to guard 

 against errors resulting from the abuse of the phrase " geological 

 contemporaneity." 



But when Professor Huxley went on to suggest that " a Devonian. 



