412 Chronicles of Science. [July, 



derings of its forefathers from one region to another, and their 

 gradual modifications of form. In looking at our English fauna, we 

 may hope to recognize certain forms as belonging to our area from 

 Palaeozoic times, others as dating from Mesozoic, others again as 

 Eocenic, others as Miocenic or later ; in some cases we shall assign 

 such an age to the order or genus, and a later age to the specific 

 modification. Professor Huxley conceives that distinct provinces 

 of the distribution of terrestrial life have existed from the earliest 

 periods — earlier than those of which we have any record. Whilst 

 in the dry land of our own area during Carboniferous times Amphibia 

 existed, in some other terrestrial provinces of that period Birds, 

 Reptiles, and Mammalia may have been developing. The Permian 

 epoch marks the beginning of a new period, and during the Trias 

 dry land existed in North America, Europe, Asia, and Africa, as it 

 does now. The mammals, birds, and reptiles developed in the pre- 

 ceding epoch spread into this great continental area called Arctogsea. 

 Depression then commenced in parts, and special developments 

 occurred in various regions. At the early part of this period, 

 Professor Huxley conceives Australia to have been separated and to 

 have remained dry land ever since. The discovery of the remark- 

 able Australian Ganoid since his address, confirms his conclusion. 

 The Mesozoic continent was probably continued across the Pacific 

 area to what is now the province of Austro-Columbia, the charac- 

 teristic fauna of which dates from this period. At a later part of 

 the Mesozoic period, upheaval of the Atlantic shore and depression 

 of the Pacific caused a westward movement of the Vertebrate fauna 

 which took possession of new lands and increased in extent up to 

 the Miocene epoch, from which period we may clearly trace all the 

 Mammalian forms characteristic of the great continental area of our 

 present world — exclusive of South America, Australia, and New 

 Zealand. From the Devonian period to the present day, the four 

 great oceans — Atlantic, Pacific, Arctic, and Antarctic — may have 

 occupied their present positions and only incessantly changed their 

 channels of communication and coast-lines. 



The attempt in this address to follow back the origin of Verte- 

 brate forms of life, needs only to be succeeded by similar efforts 

 with regard to Invertebrate groups, and more especially as to plants, 

 the same method of comparing present distribution and past, as far 

 as it is yet known, being used, and we shall ultimately attain most 

 valuable conclusions as to both Geological and Biological history. 



The palaeontology of the greater part of the earth has yet to be 

 investigated in order to bring light on this matter. 



