TlV.n60.Cf Hi 1 1 ■<. \ '' 



uorth to south would present the same geological features, 

 being oul}' a little more elongated. 



A moment's consideration of the geological position of 

 these rocks, as I have thus described it, cannot fail to show 

 that they have been deposited in a completely isolated inland 

 lake. This is, of course — independent of the direct evidence 

 bearing on the case — what Ave might have expected, as 

 geological theory generall}- tends towards a lacustrine origin 

 for most of the red Permian sandstones. 



(4.) Theories which may Account for the Origin of 

 THIS Lake. 



The question which we have now to consider is — What 

 has produced this hollow or rock basin ? Thei'e are only 

 three agents which could possibly originate a lake basin, and 

 these ai'e (a) internal movement, (b) water, or (c) ice. 



It could not have been the first of these, as there is not 

 the slightest evidence, in this case, of either the upheaval or 

 subsidence of the suri-oundiug or underlying rock, and if 

 either had taken place, signs of such movements must have 

 become apparent. 



Against water as the agent thei'e are many objections 

 of even a more decided nature than those against internal 

 movement. We have, for instance, no recent example of 

 water forming hollows at all ; in fact, how could it ? Water 

 has only an excavating power when it is in motion. To 

 move, it must have an inclination downward, or a force such 

 as Avind, to impel it. Consequently, the moment that a sur- 

 face Avhich is being denuded becomes horizontal, the motion 

 mu.st cease, and along with it of course the denuding powex*. 

 Hence the impossibility of water forming a hollow. Motion 

 in water produced by wind pre-supposes the existence of a 

 lake or sea, so that the movements ot water in that case 

 could only extend the boundaries of, not produce, a lake. 

 We are thus, so far as I can see, bound down to the last 

 alternative, viz., an ice origin. Doubtless in the present 

 state of geological knowledge, this ice theory is rather a 



