284 ON THE CAMBRIAI^ AND SILUEIAN OF THE DEE VALLEY. 



upper-Coldwell fauna ; (iv.) the character of the fauna of the beds 

 themselves, which resembles the upper-Coldwell fauna, mixed with 

 fossils occurring at a higher horizon in the Lake district, and indi- 

 cating a migration. 



These beds, although so like the upper Coldwell beds, were de- 

 posited in a shallower sea, as indicated by the micaceous character 

 of the beds, the numerous ripple-marks, and tracks and borings of 

 Annelids. 



The beds above the upper Coldwell beds of the Lake district do 

 not seem to be represented in the Dee valley ; but since the highest 

 beds of the latter area show extremely shallow-water conditions, it 

 is possible that this may be not altogether due to denudation, but 

 partly to deposition having ceased in the area for some period. 



