66 MR SMITH ON THE CHANGES 



have been sudden ; and beds of testaceous animals have 

 been entombed alive by the subsequent deposit of clay or 

 sand from a considerable depth. This is particularly ob- 

 servable in the laminated clay in which marine remains are 

 so frequently found in the basin of the Clyde. The upper 

 parts seem quite destitute of them, and it is only when the 

 excavations are made deep enough, such as in digging wells 

 and coal-pits, or in the lower beds of brick-works, that they 

 may be expected to be found. In the brick-works near 

 Glasgow, I am often told by the workmen that they are not 

 deep enough for shells. 



Such sudden changes we know have in recent times ta- 

 ken place on the west coast of America, and in Cutch ; 

 and no doubt earthquakes have accompanied the ancient 

 changes as well as those of a modern date. Fissures and 

 dislocations are occasionally to be observed in the beds of 

 sand and clay, produced probably by such causes. In an 

 excavation made at Warriston in the line of the Edin- 

 burgh and Newhaven railway, in cutting through a ridge 

 of about 400 yards long, 100 yards broad and 10 yards 

 high, the section, which was at right angles with its length, 

 exhibited numerous rents traversing the beds, which could 

 only have been produced by a sudden upheaving. A ho- 

 rizontal section would have represented the fissures as pa- 

 rallel with its length, whilst the cross one shews them 

 radiating, as it were, from a centre. The inclination of 



the beds is too great to be ascribed to original inequalities 

 in the mode of deposition. In some cases they form an angle 

 of more than 60 degrees with the horizon. Some of them 



