Notices of Memoirs — Address by Sir T. H. Holland. 457 



invariably to thickness of chalk, not length of exposure ; and though 

 it is possible that the phrase is here intended to refer to length of 

 exposure, not thickness of chalk, that theory can hardly bo reconciled 

 with the contrast he draws (p. 28) between M. pwnilus found "close 

 to the sluice " and a form of Echinocorys found " near the base of the 

 zone". The point is one of some imjiortance, for if the chalk exposed 

 is in situ right up to the stream the strike corresponds so nearly with 

 the direction of the bank between the cascade and the stream that not 

 more than 30 feet of chalk at the outside can be brought in in this 

 distance. A specimen of 31. punulus found even at the very edge of 

 the stream would then occur practically at the base of the zone, 

 which is completely at variance with all my experience elsewhere ; 

 even the 150 feet of mucronata chalk in Whitecliff Bay, and the 

 196 feet in Scratchells Bay have only yet yielded me one specimen 

 each. But if this chalk is not in situ, then the occurrence of 

 M. pumihis in it is immaterial in considering the downward range of 

 that fossil. Further, if there is no mucronata chalk in situ at the foot 

 of the cliff Barrois' reference of the chalk of the west side of Arish 

 Mell to his zone of Marsupites is not open to the criticism Dr. Rowe 

 levels at it; for it is abundantly clear that Barrois' zone of Marsupites 

 embraced the greater part, probably the whole, of the old zone of 

 A. quadratus. 



(To be concluded in the November Number.) 



zsroTiCES OIF 3yEE!]ynoiE,s. 



BEITISH ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE, 

 AUSTRALIA, AUGUST, 1914. 



I.— Address to the Geological Section by Professor Sir Thomas H. Holland, 



K.C.I.E., D.Sc, F.R.S. (President of Section C). 



{Concluded from the September Number, p. 418.) 



TO attempt a discussion of the explanations offered to account for the great 

 Upper Paleeozoic glaciation would lead us far from the present theme. The 

 question is raised merely to show that the phenomena are not consistent with 

 the supposed movement of a solid shell over a solid core assisted by an 

 intermediate molten lubricant. Geologists may be compelled to hand back the 

 theory of a molten substratum to the mathematicians and physicists for further 

 repair ; but it does not necessarily follow that a foundation theory is unsound 

 merely because it has been overloaded beyond its comprehensive strength. 



The extraordinarily great distances between the areas that show signs of 

 glaciation in Permo-Carboniferous times form a serious stumbling-block to most 

 of the explanations which have hitherto been oifered. One is almost tempted 

 in despair even to ask if it is not possible that these fragments of the old 

 Gondwana continent are now more widely separated from one another than 

 they were in Upper Palaeozoic times. It is a bold suggestion indeed that one 

 can safely put aside as absurd in geomorphology. There is nothing else 

 apparently left for us but the assumption of a general refrigeration. 



The idea of the greater inequalities of the globe being in approximately static 

 equilibrium has been recognized for many years : it was expressed by Babbage 

 and Herschel ; it was included in Archdeacon Pratt's theory of compensation ; 

 and it was accepted by Fisher as one of the fundamental fact> on which his 

 theory of mountain structure rested. But in 1889 Captain C. E. Dutton pre- 

 sented the idea " in a modified form, in anew dress, and in gi-eater detail " ; he 

 gave the idea orthodox baptism and a name, which seems to be necessary for the 



