416 RAMBLES OP A GEOLOGIST. 



I found them assuming a pale nacreous gloss, an effect, it 

 is not improbable, of their still retaining, attached to the 

 epidermis, a thin film of the original shell. The world's his- 

 tory must be vastly more voluminous now, and greatly more 

 varied in its contents, than when the stratum which they oc- 

 cupy formed the upper layer of a muddy sea-bottom, and they 

 opened their valves by myriads, to prey on the organic atoms 

 which formed their food, or shut them again, startled by the 

 shadow of the Dipterus, as he descended from the upper depths 

 of the water to prey upon them in turn. The palate of this 

 ancient ganoid is furnished with a curious dental apparatus, 

 formed apparently, like that of the recent wolf-fish, for the 

 purpose of crushing shells. 



About mid-day I set out by the mail-gig for Stromness. 

 For the first few miles the road winds through a bare, soli- 

 tary valley, overlooked by ungainly heath-covered hills of no 

 great altitude, though quite tall enough to prevent the tra- 

 veller from seeing anything but themselves. As he passes 

 on, the valley opens in front on an arm of the sea, over which 

 the range of hills on the right abruptly terminates, while that 

 on the left deflects into a line nearly parallel to the shore, 

 leaving a comparatively level strip of moory land, rather more 

 than a mile in breadth, between the steeper acclivities and 

 the beach. A tall naked house rises between the road and 

 the sea. Two low islands immediately behind it, only a few 

 acres in extent, one of them bearing a small ruin on its 

 apex, give a little variety to the central point in the prospect 

 which the naked house forms ; but the arm of the sea, bor- 

 dered, at the time I passed, by a broad brown selvage of sea- 

 weed, is as tame and flat as a Dutch lake ; the background 

 beyond, a long monotonous ridge, is bare and treeless ; and 

 in front lies the brown moory plain, bordered by the dull line 

 of hills, and darkened by scattered stacks of peat. The scene 

 is not at all such a one as a poet would, for its own sake, de- 



