254 



' Martin's Geological Memoir, and 



Outliers, of the description adverted to, appear on many of 

 the hills which are situated in advance of the great escarpment" 

 of the oolite rocks. They may be denominated outliers by 

 denudation. That of Dundry Hill {fg, 109.), near Bristol, as 



Coal Measures. 



shown in Dr. Buckland*s and Mr. Conybeare's section, already 

 referred to, is an excellent example. (See the Transactions of 

 the Geological Societi/,) It also furnishes another instance of 

 unconformable position, and shows that the inclined beds 

 beneath must have been disturbed prior to the deposition of 

 the superincumbent rocks. 



Another class Mr. Martin denominates outliers by protru- 

 sion. In this case, the stratum having been disrupted, a por- 

 tion is forced from its parallel and conformable position, so as 

 to become an elevated mass, whose sides form a considerable 

 angle with the direction of the original body whence it was 



OiUlier 



J>y JProtruMm 



110 



dislodged, {jfi^g, 110.) Whether this protrusion be " effected by 

 a separate and distinct propelling impulse, or simply by arrest, 

 by the interposition of some opposing substance, during the 

 subsidence of the main body, it is not now material to enquire." 

 Amongst the variety of derangements of stratification, may 

 be mentioned those by subsidence, the sinking of certain parts 



111 



