in the Cannel Coal of Fifeshire. 319 



clearly indicate that tlie bed in which they are found must have 

 been deposited in salt or at least brackish water, and not in a 

 fresh-water lake. 



Apparently the strongest argument, which Dr Hibbert has 

 brought forward, in favour of his theory, is the great abund- 

 ance of the shells of microscopic animals, entomostraca^ which 

 are scattered through the substance of the limestone ; and which 

 he considers to belong to the fresh-water genus Cypris. Now 

 supposing him to be correct in this, it is by no means a conclu- 

 sive proof of a lacustrine deposit ; for the animals may have 

 lived in marshes or stagnant waters, such as are common near 

 the mouths of great rivers, and have been washed into the estu- 

 ary during floods. But it is not at all clear that these shells 

 are really fresh-water. The similarity between the shells of 

 the Cypris and those of the Cytherinaof Lamarck was long ago 

 pointed out by Miiller. This is a marine genus of entomos- 

 traca ; and Miiller, in describing it, says, " Species varice in 

 Fucis et Confervis marines degunt, in flustris, praesertim in 

 lineata, delitere amant ;"* and Lamarck says that they inhabit 

 the seas of the northern latitudes.-f* I am informed by Mr 

 Lyell that Mr Lonsdale has recently discovered abundance 

 of those microscopic shells in chalk, mingled with marine 

 zoophytes and testacea ; and he adds, that if they had been met 

 with in the fresh- water deposits of the Wealden, they would un- 

 doubtedly have been called Cypris. 



Dr Hibbert observes (p. 225.), that, " in the diffusion of the 

 vegetable and animal remains through the limestone, little or no 

 order is preserved. Vegetable and animal remains are not con- 

 fined to particular seams of the rock, but may occur in any 

 part of it. Nor are they confined to the limestone itself, since 

 they have been found in argillaceous and bituminous shale both 

 above and below the bed." Now this is surely very unlike that 

 tranquil deposition which we find so generally characteristic of 

 lacustrine formations ; but it is very like that more disturbed 

 state which we might expect to find in the waters of an estuary, 

 agitated by the continued flow of a river, and by the motions of 

 the tides. 



• Otho. Frid. M'uller, Entomoslraca, Lipsise, 1785, 4to, p. 64. 

 t Lamarck, Animaux sans Vertebres, v. 125. 



6 



