150 THE CRUISE OF THE BETSEY ; OR, 



trict, differing as thoroughly from it in aspect as a bit of 

 granite differs from a bit of clay-slate ; and the whole pro- 

 spect around, save the green Liasic strip that lies along the 

 bottom of the Bay of Broadford, exhibits, true to its various 

 components, Plutonic or sedimentary, a character of pictu- 

 resque roughness or bold sublimity. The only piece of smooth, 

 level England, contained in the entire landscape, is the fossil- 

 mottled island of Pabba. "We were first struck, on landing 

 this morning, by the great number of Pinnae embedded in the 

 strata, shells varying from five to ten inches in length, 

 one species of the common flat type, exemplified in the ex- 

 isting Pinna sulcata, and another nearly quadrangular, in the 

 cross section, like the Pinna lanceolata of the Scarborough 

 limestone. The quadrangular species is more deeply crisped 

 outside than the flat one. Both species bear the longitudinal 

 groove in the centre, and, when broken across, are found to 

 contain numerous smaller shells, Terebratulae of both the 

 smooth and sulcated kinds, and a species of minute smooth 

 Pecten resembling the Pecten demissus, but smaller. The 

 Pinna?, ere they became embedded in the original sea-bottom, 

 long since hardened into rock around them, were, we find, 

 dead shells, into which, as into the dead open shells of our 

 existing beaches, smaller shells were washed by the waves. 

 Our recent Pinnae are all sedentary shells, some of them full 

 two feet in length, fastened to their places on their deep-sea 

 floors by flowing silky byssi, cables of many strands, of 

 which beautiful pieces of dress, such as gloves and hose, have 

 been manufactured. An old French naturalist, the Abbe Le 

 Pluche, tells us that " the Pinna with its fleshy tongue" (foot), 

 a rude inefficient-looking implement for work so nice, 

 " spins such threads as are more valuable than silk itself, and 

 with which the most beautiful stuffs that ever were seen have 

 been made by the Sicilian weavers." Gloves made of the 

 byssus of recent Pinnae may be seen in the British Museum. 



