392 Mr Smith 07i the Changes of the Level of the Sea. 



pected to be found. In the brick-works near Glasgow, I am 

 often told by the workman that they are not deep enough for 

 shells. 



Such sudden changes we know have in recent times taken 

 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, pro- 

 duced probably by such causes. In an excavation made in 

 the line of the Edinburgh and Leith 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, ex- 

 hibited numerous rents traversing the beds, which could only 

 have been produced by a sudden upheaving. A horizontal 

 section would have represented the fissures as parallel 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 consist of fine and coarse sand or clay, 

 and others of small fragments of coal. The section presented, 

 a beautiful miniature model of the stratification, fissures, slips, 

 and faults of a coal-field. These beds are covered by another 

 of gravel, which lies unconformable to them, and has evidently 

 been deposited immediately after, filling from above some of 

 the open fissures. It is impossible to account for these appear- 

 ances, without supposing that they are the effect of a local up- 

 heaving. 



Although, however, the changes in level might in some cases 

 have been sudden and attended with earthquakes, it is probable 

 that in others they have been slow and gradual, like those tak- 

 ing place in Sweden at the present day. Indeed, with the ex- 

 ception of the absence of works of art, nothing can more per- 

 fectly agree with the appearances of the ancient marine alluvial 

 beds than Mr LyelPs description of similar, but more recent 



