Physical Geography. 197 



amount of waste and degradation that they have under- 

 gone since that ancient time, and we may be sure that 

 it was surrounded by seas of this lower Mesozoic epoch, 

 for fragments of the Oolitic strata still surround the 

 island. This was the larger land, from which the 

 rivers flowed that deposited the fresh-water sands de- 

 scribed above. On the low banks of these rivers grew 

 many a plant now represented merely by indistinct 



impressions 



' Their meaning lost, 

 Save what remains on stone, or fragments vast ' 



in which the relics of species of Araucaria, Cycas, 

 Zamia, Screw Pine, and numerous other forms, to- 

 gether with gigantic Equisetums which grew in the still 

 waters on their borders, while Marsupial mammals on 

 the shores, and Trigonise and Terebratulse in the seas ? 

 help us to realise that the physical characteristics of 

 the time in some degree resembled that of Australia 

 in our own day, a circumstance first noticed by 

 Professor Owen. 



This state of affairs was at length partly brought to 

 an end by a gradual submergence, during which the 

 Oxford and Kimeridge Clays were deposited in open 

 seas, but the sinking of the area was not by any 

 means so great as to swallow up the old islands 

 round which the strata were formed, and which still 

 remain, much changed, as the most lofty portions of 

 Great Britain. Such fragments of the Jurassic strata 

 as still remain on the coasts of Scotland throw some 

 light on this question. 



On the east of Scotland, at and near Brora, in 

 Sutherland, the Liassic and Oolitic strata have been 

 long known, and were first described in the Journal 

 of the Geological Society in 1858 by Mr. (afterwards) 



