ADDRESS. Ixxxix 
geological period, remains of marsupials, some insectivorous, as Spalaco- 
therium and Triconodon, others with teeth like the peculiar premolars in 
the Australian genus Hypsiprymnus, have been found in the upper oolite of 
the Isle of Purbeck*. In the lower oolite at Stonesfield, Oxfordshire, mar- 
supial remains have been found having their nearest living representatives in 
the Australian genera Myrmecobius and Dasyurus. 
Thus, it would seem, that the deeper we penetrate the earth, or, in other 
words, the further we recede in time, the more completely are we absolved 
from the present laws of geographical distribution. In comparing the mam- 
malian fossils found in British pleistocene and pliocene beds, we have often 
to travel to Asia or Africa for their homologues. In the miocene and eocene 
strata some fossils occur which compel us to go to America for the nearest 
representatives. To match the mammalian remains from the English oolitic 
formations, we must bring species from the Antipodes. 
These are truly most suggestive facts, unrecognized until science looked 
abroad upon the world. If the present laws of geographical distribution 
depend, in an important degree, upon the present configuration and position 
of continents and islands, what a total change in the geographical character 
of the earth’s surface must have taken place since the ‘ Stonesfield slate’ was 
deposited in what now forms the county of Oxfordshire ! 
These and the like considerations from the modifications of geographical 
distribution of particular forms or groups of animals warn us how inadequate 
must be the phenomena connected with the present distribution of land and 
sea to guide to the determination of the primary ontological divisions of the 
earth’s surface. Some of the latest contributions to this most interesting 
branch of Natural History have been the result of endeavours to determine 
whether, and how many, distinct creations of plants and animals have taken 
place. But, I would submit, that the discovery of two portions of the 
globe, of which the respective Faunz and Flore are different, by no means 
affords the requisite basis for concluding as to distinct acts of creation. 
Such conclusion is associated, perhaps unconsciously, with the idea of the 
historical date of creative acts: it presupposes that the portion of the globe 
so investigated by the botanist and zoologist has been a separate and primitive 
creation,—that its geographical limits and features are still in the main what 
they were when the creative fiat went forth. 
But Geology has demonstrated that such is by no means the case with 
respect to the portions of dry land now termed continenis and islands. The 
incalculable vistas of time past into which the same science has thrown 
light are also shown to have been periods during which the relative positions 
of land and sea have been ever changing. 
Already the directions, and to a certain extent the forms of the submerged 
tracts that once joined what now are islands to continents, and which once 
united now separate or nearly disjoined continents by broad tracts of conti- 
* These fossils are due to the researches of Messrs. Brodie and Beckles. 
