1850.] HARKNESS — ^NEW RED SANDSTONE, DUMFRIESSHIRE. 397 



some parts with beds of clay, some of which are nearly a foot in 

 thickness. These clay beds never occur in the sandstone deposits of 

 Dumfries. In both Lancashire and Cheshire they are commonly met 

 with in the higher portion of the new red sandstone. 



On the under surfaces of the sandstone strata about Annan, there 

 sometimes occur marks of the footsteps of the Cheirotherium in relief, 

 like those of the Cheshire sandstone, as well as casts of the lines of 

 desiccation. In the adjoining parish of Kirkpatrick Fleming, which 

 lies eastward, the sandstone affords the same appearances. Here the 

 beds of red shale, interstratified with the solid rock, are more nume- 

 rous than in the immediate neighbourhood of Annan. At the Cove 

 quarry, the sandstone and the shale beds have undergone an entire 

 change both in colour and texture. The sandstone is white and fine- 

 grained, but soft when first quarried ; by exposure to the atmosphere, 

 however, it becomes harder. The strata are of different thicknesses, 

 and interstratified with beds of shale of a red and blue colour. 



The whole of these deposits east of the river Annan are evidently 

 superior in position to those in the neighbourhood of Dumfries ; and 

 this inference is supported by the absence of interstratified beds of 

 clay amongst the sandstone in this latter locality, as well as by the 

 difference of the footsteps. That the higher beds overlying the 

 Dumfries conglomerate were deposited before any of the Annan beds, 

 is certain ; but whether at the former place the representatives of the 

 higher sandstones of Annan have been removed by denudation, or 

 whether the lower beds of the former locality have been elevated 

 above the surface of the sea previous to the deposition of the latter, 

 is quite a matter of uncertainty. 



The sandstone formation in the neighbourhood of Dumfries may 

 with propriety be divided into three deposits: viz. 1st, the thick- 

 bedded sandstones with their overlying flaggy strata, altogether more 

 than 130 yards in thickness ; 2ndly, the conglomerate, 100 yards 

 thick ; and 3rdly, the fine-grained soft sandstone covering the conglo- 

 merate, and also about 100 yards thick. The lowest and regular beds 

 of sandstone seem to have been deposited by gentle and uniform cur- 

 rents ; but after a deposition of a considerable thickness of this sand, 

 there appears to have been slight interruption, during which the sand 

 became more or less consolidated, previous to the deposition of fresh 

 material. In the flaggy beds the interruptions were far more fre- 

 quent, and another agent, possibly the polishing power of the tidal 

 waves, produced on the surfaces of the flags the burnished purple 

 aspect already described. 



That the action of sea-water can produce such an aspect, Darwin 

 in his interesting narrative affords us an example. He states, that 

 not far from the city of Bahia he observed a coating on the rocks 

 of a rich brown colour, composed of ferruginous matter, occurring 

 within the limits of the tidal waves. This coating he refers to the 

 polishing power of the rise and fall of the tidal waves ; and as 

 Humboldt states that the same occurrence is met with at the cata- 

 racts of the Orinoco, Niger, and Congo, and has referred it to the 

 friction produced by water in motion, it is probable that the bur- 



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