POST-TERTIARY FOSSILIFEROUS DEPOSITS. 



57 



Avherever any jutting point has saved them from denudation. In some places a bed of 

 Mya truncata runs under the turf, and is above high-tide-mark, while the Boulder Clay is 

 seen beneath it, the shell-bed having been more perfectly protected than on the opposite 

 side of the water ; Saxicava Norvegica of very large size is in situ, and any lump of clay 

 yields numerous examples of Tellina calcarea. 



« 2. Balnakeaile Bay. — In this bay, which is almost directly opposite to Colintraive 



Pier, the glacial beds have been well preserved ; they are cut through by a small stream 

 which discharges itself into the sea in the middle of the bay, and exposes the clay with 

 characteristic Arctic species in situ,. On the left of the stream the shell-bed extends 

 under a bank of sand and gravel, rising to a height of twenty feet ; and it also crops 

 out in the wood, a quarter of a mile inland, on the same side of the stream. The 

 nature of the matrix in which the shells are found varies from a loose sand to a 

 tenacious clay. 



Following the Rothesay Road, in a slight bend of the Kyles opposite the first farm- 

 house, the shell-bed has been found in great perfection. It is now almost washed away, 

 but a few years ago the remains of an Arctic fauna were multitudinous. A bed of Peden 

 Islandicus existed and many of the specimens had Balcmus porcatus attached to their 

 upper valves ; B.porccdm adhered also to large boulders on the shore. In those beds we 

 have also found Balmms cariosus (Darwin) and Modiolaria nigra ; and Saxicava Norvegica 

 was in great perfection. The beds occur in the same order as at Tigli-na-bruaich, and 

 the shell-bed extends from high-tide-mark towards the sea, at about half-tide being at 

 its thickest. Before it can be well seen a foot or more of sand and gravel must be 

 removed. Collections made from the mere surface debris are worthless, since they will 

 be found to contain Arctic, raised-beach, and recent species intermixed in inextricable 

 confusion. 



3. Ettrick Bay. — This bay on the Bute shore, near the westerly entrance to the Kyles, 

 is so completely covered with sand as to obscure the separate beds. It is noteworthy, 

 however, as the locality in which Astarte borealis may be found in great abundance, 

 generally in single valves, although we have obtained a perfect specimen. 



Height above the sea from half-tide to about fifteen feet. 



The following Ostracoda were found 



Cythere pellucida, Baird. 



— viridis, Miiller. 



— luiea, Miiller. 



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