BIOLOGICAL CHANGE IN GEOLOGICAL TIME. 



117 



admiration of the manner in which this paper has been brought 

 before us. Of course we all know Professor Lobley is a first-class 

 authority on pala3ontological matters ; and whether we agree with 

 his views as to the origin and progress of species and forms or not, 

 we must admit that he has handled his subject in a very eloquent 

 and interesting manner. There are, however, several points, not so 

 much connected with the palsoontology as with the physiography of 

 the subject, which I wish to call his attention to. In the first place, i 

 I do not go with him so far as he does regarding the extent of the j 

 destruction of the various formations which he indicates in his [ 

 paper. 



He seems to suggest that the mountains of Wales and other 

 mountain regions to the north of Wales and the British Isles 

 were covered over by strata belonging to the Jurassic and 

 Cretaceous periods. I do not think this was the case at all. This 

 is a subject I have dealt with in a work which lies on the table and 

 which I would ask Professor Lobley to look at and see if he does not 

 agree with me. Unquestionably the Silurian region of Wales and 

 the north of Scotland and the Carboniferous region forming the 

 " backbone of England " were land surfaces at the time when the 

 Oolites, the Cretaceous limestone (or the Chalk) were being formed in 

 submerged areas to the south. The waters of these seas did not 

 cover these old regions at all. They were land surfaces during that 

 period, and therefore the destruction of these formations did not go 

 on to the extent which the author of the paper seems to assume. 

 These formations as they approached the old land surface gradually 

 thinned out into thinner and thinner dimensions, and therefore 

 were ultimately denuded round their margins on the uprising of the 

 lands to their present position. 



With regard to the uniformity of denudation in these periods, 

 I fear I cannot agree with the author of the paper. I think the ] 

 denudation of strata may have been vastly more rapid in very 

 ancient times than it is at the present day. One reason which may ; 

 be adduced is the greater proximity of the moon to the earth in early 

 geological times. If the moon was originally thrown off from the 

 earth it inevitably increased its distance to its present state, where 

 it seems to be permanently at a certain distance from the earth 

 owing to the balance between gravitation and centrifugal force. 

 During the period of gradual widening of the distance there must 



