294 Scientific Geology. 



slate, one or two hundred feet high ; and the facts now related seem 

 incapable of explanation, but by supposing a prodigious blow to have 

 been given to the top of the hill, directed from east to west obliquely 

 downwards. But what natural agent could have exerted such a force 

 on such a point, I confess myself utterly at a loss to imagine. Among 

 the endless variety of geological hypotheses that have been proposed, 

 I could not call one to mind, which would apply at all to this phe- 

 nomenon, unless it be the supposition formerly advanced, that the last 

 deluge might have been produced by the impinging of a comet 

 against the earth ! I confess I could not but enquire whether this 

 might not have been the point of contact ! 



Disturbance in the Argillaceous Slate : Guilford, Vt. 



Theoretical Considerations. 



When we consider the nature of the materials composing argilla- 

 ceous slate, it seems difficult to assign any other origin to this rock, 

 than deposition from water. Indeed, one has only to look at a clay 

 bed, such as occurs in some of the tertiary strata, which we are sure 

 must have been deposited from water, to be satisfied that he has be- 

 fore him clay slate in its unfinished state ; since nothing but the con- 

 solidation of the clay bed is wanting to convert it into perfect clay 

 slate. But what agency could have effected this consolidation? Mere 

 desiccation would do much ; but it is difficult to believe that this could 



