A SUMMER RAMBLE AMONG THE HEBRIDES. 53 



promiscuously throughout the general mass. Leaving, how- 

 ever, these oysters of the Oolite, which never net inclosed nor 

 drag disturbed, though they must have formed the food of 

 many an extinct order of fish, mayhap reptile, we pass 

 on in a south-western direction, descending in the geological 

 scale as we go, until we reach the southern side of the Bay 

 of Laig. And thepe, far below tidemark, we find a dark- 

 coloured argillaceous shale of the Lias, greatly obscured by 

 boulders of trap, the only deposit of the Liasic formation in 

 the island. 



A line of trap-hills that rises along the shore seems as if 

 it had strewed half its materials over the beach. The rug- 

 ged blocks lie thick as stones in a causeway, down to the line 

 of low ebb, memorials of a time when the surf dashed 

 against the shattered bases of the trap-hills, now elevated 

 considerably beyond its reach ; and we can catch but partial 

 glimpses of the shale below. Wherever access to it can be 

 had, we find it richly fossiliferous ; but its organisms, with 

 the exception of its Belemnites, are very imperfectly pre- 

 served I dug up from under the trap-blocks some of the 

 common Liasic Ammonites of the north-eastern coast of Scoi- 

 land, a few of the septa of a large Nautilus, broken pieces of 

 wood, and half-effaced casts of what seems a branched coral ; 

 but only minute portions of the shells have been converted 

 into stone ; here and there a few chambers in the whorls of 

 an Ammonite or Nautilus, though the outline of the entire 

 organism lies impressed in the shale ; and the ligneous and 

 polyparious fossils we find in a still greater state of decay. 

 The Belemnite alone, as is common with this robust fossil, 



so often the sole survivor of its many contemporaries, has 



preserved its structure entire. I disinterred from the shale 

 good specimens of the Belemnite sulcatus and Belemnite 

 dongatus, and found, detached on the surface of the bed, a 

 fragment of a singularly large Belemnite, a full inch and a 



