T. Mellard Reade — A Cooling and Shrinking Olohe. 203 



On the other hand, I have been able to determine with more or 

 less certainty that the structure of SoJenopora is truly cellular and 

 not tubular, a determination which Prof. Nicholson clearly foresaw 

 as the possible result of further investigation. I have shown that 

 the structure of the cells and cell-walls and the mode of growth 

 are, in certain cases, exceedingly similar to those of certain recent 

 and extinct Coi-allineas ; and I have further shown that the com- 

 paratively large size of the cells in Solenopora need not necessarily 

 be a barrier to our regarding the genus as truly referable to the 

 calcareous Algae. Lastly, I have been able to demonstrate in 

 some forms of Solenopora the existence of structures, which 

 in all essential respects may be fairly compared, some with the 

 " tetrasporangia," and others with the " conceptacles " of recent 

 Corallinese. 



Upon the whole, therefore, the balance of evidence seems to be 

 unequivocally in favour of the reference of the genus Solenopora to 

 the series of the Nullipores. Should this view be finally established, 

 it will be an interesting proof of the extent to which the calcareous 

 Algce have taken part in the formation of the older of the Palaeozoic 

 limestones, as they are already known to have done in the case of 

 some of the Tertiary and Secondary limestones. This proof will 

 be still further enforced if, as seems extremely probable, it should 

 ultimately be shown that Girvanella, Nich. and Eth., is really 

 referable to the Siphonece verticillatcB. 



III. — On the Eesults of Unsymmetrioal Cooling and Kedistri- 

 BUTiON OF Temperature in a Shrinking Globe as applied to 

 THE Origin of Mountain Ranges.^ 



H 



By T. Mellard Readb, C.E., F.G.S., etc. 



AVING been honoured by an invitation to state to your Society 

 the physical principles upon which my Theory of the Origin 

 of Mountain Ranges is founded, I do so with the greater pleasure 

 knowing that it will receive a searching criticism at your hands, 

 from which I hope to derive considerable benefit. My audience 

 hitherto having been mostly geological, the physical principles 

 involved have been to some extent subordinated to geological 

 conditions. 



In addressing you I purpose adopting the opposite method to that 

 in which I have expounded the process of Mountain formation, as 

 I conceive it to have taken place, to my geological brethren. In 

 the natural way in which the subject has developed itself in my 

 own mind, I commenced with the facts of geology and reasoned 

 backwards to the principles. On the present occasion I intend to 

 state a few of the leading physical principles, and to unfold how 

 the facts of Geology, of Mountain Upheaval and Structure have 

 come about. 



* Bead before the Liverpool Physical Society, January 29th, 1894. 



