FREE BOOKS

Author's List




PREV.   NEXT  
|<   109   110   111   112   113   114   115   116   117   118   119   120   121   122   123   124   125   126   127   128   129   130   131   132   133  
134   135   136   137   138   139   140   141   142   143   144   145   146   147   148   149   150   151   152   153   154   155   156   157   158   >>   >|  
on the planes of which I could trace with great distinctness ripple markings; but in vain did I explore their numerous folds for the plates, scales, and fucoid impressions which abound in the gray argillaceous beds of the shores of the Moray and Cromarty Friths. It would, however, be rash to pronounce them non-fossiliferous, after the hasty search of a single morning,--unpardonably so in one who had spent very many mornings in putting to the question the gray stratified beds of Ross and Cromarty, ere he succeeded in extorting from them the secret of their organic riches. We set out about half-past ten for Scuir More, through the Red Sandstone valley in which Loch Scresort terminates, with one of Mr. Swanson's people, a young active lad of twenty, for our guide. In passing upwards for nearly a mile along the stream that falls into the upper part of the loch, and lays bare the strata, we saw no change in the character of the sandstone. Red arenaceous beds of great thickness alternate with grayish-colored bands, composed of a ripple-marked micaceous slate and a stratified clay. For a depth of full three thousand feet, and I know not how much more,--for I lacked time to trace it further,--the deposit presents no other variety: the thick red bed of at least a hundred yards succeeds the thin gray band of from three to six feet, and is succeeded by a similar gray band in turn. The ripple-marks I found as sharply relieved in some of the folds as if the wavy undulations to which they owed their origin had passed over them within the hour. The comparatively small size of their alternating ridges and furrows give evidence that the waters beneath which they had formed had been of no very profound depth. In the upper part of the valley, which is bare, trackless, and solitary, with a high monotonous sandstone ridge bounding it on the one side, and a line of gloomy trap-hills rising over it on the other, the edges of the strata, where they protrude through the mingled heath and moss, exhibit the mysterious scratchings and polishings now so generally connected with the glacial theory of Agassiz. The scratchings run in nearly the line of the valley, which exhibits no trace of moraines; and they seem to have been produced rather by the operation of those extensively developed causes, whatever their nature, that have at once left their mark on the sides and summits of some of our highest hills, and the rocks and boulders of some of our
PREV.   NEXT  
|<   109   110   111   112   113   114   115   116   117   118   119   120   121   122   123   124   125   126   127   128   129   130   131   132   133  
134   135   136   137   138   139   140   141   142   143   144   145   146   147   148   149   150   151   152   153   154   155   156   157   158   >>   >|  



Top keywords:
ripple
 

valley

 

scratchings

 

strata

 

stratified

 
succeeded
 
sandstone
 

Cromarty

 
origin
 

passed


deposit

 

comparatively

 
presents
 

variety

 
sharply
 

relieved

 
similar
 
alternating
 

succeeds

 

hundred


undulations

 

produced

 

operation

 

moraines

 

exhibits

 

glacial

 

connected

 

theory

 

Agassiz

 

extensively


developed

 
summits
 

highest

 

boulders

 

nature

 
generally
 

solitary

 
trackless
 

monotonous

 
profound

formed
 

furrows

 
evidence
 
waters
 

beneath

 

bounding

 
gloomy
 

exhibit

 
mysterious
 

polishings