296 Hoyal Society : — - 



whose notions of the depth at which the sediments containing Inver- 

 tebrata can be deposited are indefinite. These researches contribute 

 to more exact knowledge, and they will materially assist the de- 

 velopment of those hypotheses which are current amongst advanced 

 geologists into fixed theories. I do not think that any geological 

 theory worthy of the term, and which has originated from geological 

 induction, will be upset by these careful investigations into the 

 bathymetrical distribution of life and temperature. The theories 

 involving pressure and the intensity of the hardness of deep-sea 

 deposits win suffer from the researches ; but many difficulties in the 

 way of the palaeontologist will be removed. The researches tend to 

 explain the occurrence of a magnificent deep-sea coral-fauna in the 

 Puloeozoic times in higli latitudes, and of Jurassic and Cainozoic 

 faunas on the same area, and they favour the doctrines of uniformity. 

 They explain the cosmopolitan nature of many organisms, past and 

 present, which were credited with a deep-sea habitat, and they 

 afford the foundations for a theory upon the world-wide distribution 

 of many forms during every geological formation. 



It is not advisable, however, to make too much of the interesting 

 identities and resemblances of some of the deep-sea and abyssal 

 forms Avith those of such periods as the Cretaceous, for instance. In 

 the early days of geological science there was a favourite theory that 

 at the expiration of a period the whole of the life of the globe was 

 destroyed, and that at the commencement of the succeeding age a 

 new creation took place. There were as many destructions and 

 creations as periods ; or, to use the words of an American geologist, 

 there was a succession of platforms. This theory held back the 

 science, just as the theory that the sun revolved round the earth re- 

 tarded the progress of astronomy. Moreover it had that armour of 

 sanctity to protect it which is so hard to pierce by the most reason- 

 able opposition. Nevertheless every now and then a geologist re- 

 cognized the same fossils in rocks which belonged to different periods. 

 A magnificent essay hj Edward Forbes on the Cretaceous Fossils of 

 Southern India, a wonderful production and far before its age*, gave 

 hope and confidence to the few palceontologists who began to assert 

 that periods were perfectly artificial notions — that it did not follow, 

 because one set of deposits was forming in one part of the world, 

 others exactly corresponding to it elsewhere, so far as the organic 

 remains are concerned, were contemporaneous — and that life had 

 progressed on the globe continuously and without a break from the 

 dawn of it to the present time. 



The persistence of some species through great vertical ranges of 

 strata, and the relation between the world-wide distribution of forms 

 and this pei'sistence were noticed by D'Archiac, De Yerneuil, Forbes, 

 and others. The identity of some species in the remote natural- 

 history provinces of the existing state of things was established in 

 spite of the dogmatic opposition of authorities ; and then geologists 

 accepted the theories that there were several natural-history pro- 

 vinces during every artificial period, that some species lived longer 

 * Quart. Jouru. Geol, Soc. vol, i. p. 79. 



