Geological Society of Glasgow. 557 



Northern Drift indicates a Glacial. This Pluvial period must have 

 immediately preceded the true Historical period. 



Gkological Society of Glasgow. — 1. The annual address in con- 

 nection with the opening of the winter session of this Society was 

 delivered on October 31st, 1867, by Professor John Young, M.D., 

 F.R.S.E., the President. The subject he had chosen from his own 

 observations was " The evidence of zoological continuity in the 

 past." In speaking of the terms 'high' and 'low' as applied to 

 organisms — terms used too often very vaguely — the lecturer put 

 several cases. Amongst others, the comparison of the lamb and the 

 human infant immediately after birth, which shows a superiority on 

 the part of the former, and raises the question, as regards the inver- 

 tebrated animals, as to the period of life which supplies data for the 

 decision as to rank. In dealing with the origin of species and the 

 evidences of zoological continuity. Dr. Young stated that, from the 

 earliest times, there must always have been suitable localities for 

 some forms of life. The lecturer passed in review the fossils of the 

 Paleozoic and Triassic strata, and showed that, so far as the structure 

 of their hard parts is concerned, it cannot be affirmed as an absolute 

 trath in all cases — though there is great probability in some — that 

 there has been progress from the earlier to the more recent forms. 

 The fish and labyrinthodonts were the groups chiefly referred to, 

 and in these, especially in the former, it was pointed out that 

 structures once relied on as proof of embryonic condition had since 

 (as the heterocercal tail of fishes) proved to be the rule in many, if not 

 all, living genera. Dr. Young then described at some length the 

 structure of the amphibians, or frogs and salamanders, with their 

 allies, and indicated the points on which they resemble fish on the 

 one hand and reptiles on the other. The amphibians were selected 

 because the classification of the series shows a gradation of struc- 

 tures generally parallel to the development of the tadpole into the 

 frog. He then pointed out that the labyrinthodonts belonged to the 

 lower divisions of the amphibians, but that at their first appearance 

 in the Coal they present two forms of very unequal development as 

 regards their skeleton, just as at the present day amphibians co-exist 

 of all degrees of development. It was next shown that functionally 

 the sharks are, in many respects, better endowed than a large section 

 of the amphibians. The latter, however, are ranked higher than the 

 former. In the lower members, however, of a class there is no 

 degradation in the sense of backward progress, where structural 

 inferiority is found, it is an arrest of development ; where the parts 

 are fewer, it is because the functions are more limited. There are but 

 two ways of the origin of living things ; not speaking of the first 

 origin of all, but of the appearance of new forms in a series already 

 existing. The one of these ways is that of a relation by descent, 

 with modification ; the other is the organization of inert matter. 

 The one is within the limits of science, the other is wholly beyond 

 the pale. We must either believe in the hypothesis of special 

 creation, or in that of zoological continuity. The former involves 



