50 MR SMITH ON THE CHANGES 



My attention was first called to the subject by the dis- 

 covery of marine shells, agreeing in general with those of 

 the adjoining seas, embedded in blue clay, at Ardincaple, 

 the seat of Lord John Campbell, in Dumbartonshire. At 

 that time it was usual to ascribe all such appearances to 

 diluvial action ; and although the shells bore no marks of 

 violent transportation, the bivalves being entire, with the 

 epidermis uninjured, and in their natural position ; yet, as 

 the distance from the sea was small, I imagined they might 

 have been protected from injury by having been lodged in 

 an eddy. Two of the shells appeared to differ from any 

 known species ; one of them a Tellina ( T. approxima)^ is 

 so common, as in many localities to become characteristic 

 of this deposit. It resembles the T. tenuis, but is dis- 

 tinguished by a brown epidermis ; the other resembled a 

 Natica, but was destitute of the umbilicus. The only spe- 

 cimen procured of this shell I unfortunately broke, but not 

 until a sketch of it had been taken.""" Lord John Camp- 

 bell was kind enough to order a new excavation to be 

 made, in hopes of finding other specimens, but without 

 success. 



Soon after this, Mr Thomas Thomson gave an interest- 

 ing description of a similar deposit at Dalmuir in Dumbar- 

 tonshire, in the Records of General Science.-f- He collected 

 twenty-nine species, which were submitted to the inspection 

 of Mr Sowerby, who pronounced three of them to differ from 

 any known recent British shells ; one of them was said to 

 be Natica glaueinoides, a crag fossil ; another, Fusus lamel- 

 losus, which had only been observed about the Straits of 

 Magellan ; and a third, Buccinum striatum, an unknown 

 species. This remarkable fact, coupled with my own ob- 



* Plate XLV. Fig. 18. t Vol i. p. 131. 



