Marine Deposits on the Margin of Loch Lomond. 73 



tenantry, but is not much esteemed for agricultural pur- 

 poses. It is highly crystalline in its fracture, appearing to 

 be irregular layers of crystals separated by quartz and clay. 

 There are other two places which afford shells, in very 

 different circumstances. These points are similar in situa- 

 tion ; both are in slight bays opening to the north, and pre- 

 senting a steep gravelly beach to the water. One of them 

 is on the island of Inch Lonach, opposite to the village of 

 Luss ; and the other on the lands of H. Macdonald Buchan- 

 nan, Esq., near the south-east angle of the lake. The shells 

 begin to appear about half-way between the highest and low- 

 est, or the winter and summer, surfaces of the water, which 

 varies in this respect about six feet. After removing a slight 

 covering of coarse gravel, we find a thin bed of clay, of dif- 

 ferent shades of brown, passing into yellow colours, as we 

 descend. In the upper, or brown clay, are found shells of 

 the following species. Those marked ? are doubtful. Buc- 

 cinum reticulum f Nerita glaucina, Tellina tenuis ? Cardium 

 edule, Venus striatula, Venus Islandica, Nucula rostrata 

 young, Pecten obsoletus. Anomia ephippium young, Balanus 

 communis, Balanus rugosus. Echinus escnlentus. A skil- 

 ful conchologist would discover many others, from the nu- 

 merous traces of them in the clay. Those shells appear to 

 have been deposited generally in an entire state, and many 

 are found with both valves in their natural position. The 

 Balanus is still slightly attached to the Venus or Pecten ; 

 and the spines of the Echinus are found clustered in the clay 

 inclosing its fragments ; so that they must have been either 

 covered by water to a considerable depth, or thrown on a 

 beach not much exposed to waves. Few of them, however, 

 can be extracted entire, as several of the species are always 

 in a state of gritty chalk ; but many complete and beautiful 

 specimens of the Pecten can easily be procured. Few of 

 their fragments appear on the exposed part of the beach, 

 but, during summer, many may be seen a few feet under wa- 

 ter. Those deposites cannot be more than about twenty-two 

 feet above the present level of the sea. It is probable that 

 an attentive inspection of the margin of the lake would dis- 

 cover many others similar to them. A little attention may 



