342 



rising one above the other, until their termination at the 

 surface of the plain. These slides are of various dimen- 

 sions, some of them extending to a considerable magni- 

 tude ; and when their edges become exposed, from exca- 

 vations for the purpose of obtaining the brown sand, or 

 the clays in which it is embraced, the facts there deve- 

 loped might easily deceive the eye of a spectator, by dis- 

 closing to his view the appearances of a repetition of simi- 

 lar deposits widely separated from each other in position, 

 whereas they are in reality a part and parcel of the same 

 stratification. 



Most of these slides exhibit evidences of a very slow 

 and gradual movement of the mass in their progress on- 

 ward. In many situations, tlie beds of sand and gravel 

 which they contain, and the various strata of clay which 

 compose their structure, however distorted and disarranged 

 they may appear, disclose no further indications of any 

 disturbance, either by fracture or otherwise, than those 

 produced at the time of their original deposition : they 

 perfectly correspond in every respect with the same'ior- 

 mation in its natural position many feet above. In other 

 instances, where the movements have evidently been more 

 rapid and irregular in their action, the different materials 

 of which they were constructed appear to have been frac- 

 tured and tumbled about into the utmost degree of confu- 

 sion. In several other situations, where excavations for 

 economical applications have been made along the sloping 

 sides of these ravines, the peculiar action of the slides is 

 well exhibited. In frequent instances, most generally 

 after heavy torrents of rain, the progress of railroad cars 

 has been seriously impeded by prodigious quantities of 

 these materials having been suddenly thrown over the 

 track, so as to require the constant employment of a large 

 number of workmen in their removal. The only method 

 to remedy such an inconvenience is, if practicaWe, to con- 

 struct the embankment from the edge of the road at the 



