Mr HOPKINS, ON RESEARCHES IN PHYSICAL GEOLOGY. 5 



«. The inclination of the plane of the fissure to a vertical plane, which 

 IS frequently termed by the miners of the more northern districts the 

 hade of the vein, and by the Cornish miners its mderUe, is very un- 

 certain, amounting not unfrequently to as much perhaps as 20", generally 

 however, to considerably less, though in particular cases to considerably 

 more. It will sometimes vary at different depths along the same vertical 

 line, so that in some instances, when the hade is small, it will be in 

 one direction in the upper, and in the contrary direction in the lower 

 part of the vein. Upon the whole, however, the hade is not very great, 

 and tolerably regular in each vein*. 



M. Classes of the adjoining rock, more or less perfectly detached 

 from it, are frequently found imbedded in the matter which occupies 

 the fissure f. 



V. Apparent or real displacements in the position of a vein are 

 frequently observed at its intersection with another vein, or with some 

 particular stratified bed, which is generally found to be a bed of moist 

 slimy clay. These intersections are of various kinds. 



o. First, that of a vertical or nearly vertical vein, with a clay bed 

 horizontal, or nearly so. The displacements in this case are shewn in 

 the figures annexed, which represent vertical sections perpendicular to 

 the plane of the vein. 



It is manifest that here either the part of the vein above the stratum 

 cd has been moved, or that below it, or both, if the two portions were 

 ever in the same plane. 



• The underlie of the Cornisli lodes is frequently greater, I conceive, than in our other 

 mining districts. It may possibly also be more irregular. 



t These insulated masses are frequently termed by miners. Riders. 



