472 Trcmsacdons. — Geology. 



contend, could only liave commenced when the temperature of the surface 

 of the ground within those regions had fallen permanently below 32° Fahr. 

 Since my former paper was read before this society, the May number of the 

 "Quarterly Journal of the Geological Society" has been received, and I 

 find that the same subject which was dealt with by me in my former paper 

 had been referred to by Professor Duncan, President of the Society, in his 

 anniversary address. He points out that in the science of geology "strict 

 uniformitarianism is giving way to a school which insists upon the recog- 

 nition of a scientific cosmogony, which attempts the study of the mutations 

 of the globe from the beginning, from the example of stellar and solar 

 changes, and which considers that the principal factors in terrestrial altera- 

 tions (the solar heat and the residual heat of the earth) are energies under- 

 going only a definite amount of reversible and more or less irreversible 

 transformation." And he adds that it follows, as a result of the investiga- 

 tions of this school, that "in the earlier geological ages, the extent and 

 rapidity of the successive changes were greater than in the modern example, 

 that the rigidity of the globe was less, that the internal heat and its expres- 

 sion in temperature at the surface were greater, and that the meteorology 

 was such that the wear and tear of world-wide nature was larger in its 

 annual amount." Further on, in the same address, the learned Professor 

 remarks, "that it must be acknowledged that a permanent increase of a few 

 degrees of the temperature of the waters would kill off many species, and 

 that the whole flora and fauna would cease to exist were the average heat 

 double what it now is; that the same result would follow a moderate 

 increase of the heat of the soil with regard to the plants ; and that if the 

 estimated amount of the heat radiated year by jcri-, after conduction from 

 Vtdthin, relates entirely or mainly to a former much greater annual average, 

 all being residual in its nature, the question of the possible lapse of time 

 since the surface was cool enough to permit of life arises, and has been ably 

 used in argument against absolute uniformitarianism." 



I ought not to make these quotations, however, without adding, that 

 Professor Duncan does not go deeply into the question in the aspect pre- 

 sented in my own paper, nor can I cite his address as being altogether in 

 supx^ort of my views ; but it was satisfactory to me to find that such a 

 speculation as that in which I ventured to indulge, was not altogether with- 

 out interest or foundation in connection with geology as a practical science. 

 My own views, put in concrete form, are these : That the arctic and 

 antarctic regions were those which first presented climatal conditions 

 suited to the existence of life, inasmuch as those regions must have been 

 the first to cool down sufficiently to admit of water resting upon them in a 

 permanently liquid condition, That, as a consequence naturally following 



