496 



THE GEOLOGIST. 



Certain horizontal areas, or provinces, have been characterized by the entire 

 assemblage of animals and plants constituting their population, of which a con- 

 siderable proportion is peculiar to each province, and the majority of each species 

 have their areas of maximum development within it. 



Of the provinces of Marine Life, that much lamented, far-seeing, and genial 

 philosopher, Edward Forbes, has provisionally defined 25, 



The same physical conditions are associated with a certain similarity between 

 the animals of different provinces. Where those provinces are proximate, such 

 likeness is due to the identity or close affinity of the species ; but where the 

 provinces are remote the resemblance is one of analogy, and species of different 

 genera or families represent each other. 



A second mode of expressing the ascertained facts of the geographical distribu- 

 tion of marine animals is by tracts called "Homoiozoic Belts," bounded by climatal 

 lines ; which are not, however, parallel with lines of latitude, but undulate in 

 subordination to climatal influences of warm or cold oceanic currents, relations of 

 land to water, &c. Of these belts nine are defined ; one equatorial, with four to 

 the north and four to the south, which are mutually representative. 



But the most interesting form of expression of the distribution of marine life is 

 that which parallels the perpendicular distribution of plants, according to the 

 depth at which they live, in a manner very analogous to the changes in the forms 

 and species of vegetation observed in the ascent of a tropical mountain, Edward 

 Forbes has expressed these facts by defining five bathymetrical zones, or belts of 

 depth, which he calls, — 1, Littoral; 2, Circumlittoral; 3, Median; 4, Infra- 

 median ; 5, Abyssal, 



The life- forms of these zones vary, of course, according to the naf-.ure of the 

 sea-bottom ; and are modified by those primitive or creative laws that have caused 

 representative species in distant localities under like physical conditions, — species 

 related by analogy. 



Our space will not permit our proceeding step by step through this portion of 

 the Professor's address, at any rate in this number, but the reference to the bear- 

 ing of the ancient relations in geological eras of land and sea in the consideration 

 of the question whether, and how many, distinct creations of plants and animals 

 have taken place ? is too important a topic to be omitted. The discovery of two 

 portions of the globe, of which the respective faunte and florae are different, by no 

 means affords the requisite basis for concluding as to distinct acts of creation. 

 Such conclusion, unconsciously associated with the idea of the historical date of 

 creative acts, pre-supposes that the portion of the globe so investigated by the 

 botanist and zoologist has been a separate creation — that its geographical limits 

 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 ; the incalculable 

 vistas of time past into which this science has thrown light are shown to have 

 been periods during which the relative positions of land and sea have been ever 

 changing ; and already the directions, and, to an extent, the forms of the submerged 

 tracts that once joined what are now islands to the primeval continents, are 

 beginning to be laid down on geological maps. 



These phenomena shake our confidence in the conclusion that the Apteryx of 

 New Zealand and the Red-grouse of England were distinct creations in and for 

 those islands respectively. Always, also, it may be well to bear in mind that 

 by the word "creation," the zoologist means "a process he knows not what." 

 Science has not ascertained the secondary causes that operated when the " earth 

 brought forth grass and herb yielding seed after its kind," and when " the waters 

 brought forth abundantly the moving creature that hath life." And supposing 

 both the fact and the whole process of the so-called " spontaneous generation" of 

 a fruit-bearing tree, or of a fish, were scientifically demonstrated, we should still 

 retain as strongly the idea, which is the chief of the " mode " or " group of ideas " 

 we call =1 creation," viz., that the process was ordained by and had originated from 

 an all-wise and powerful First Cause of all things. 



Keniarks on Sanitary Science, Agriculture, the Water-supply and Drainage of 



