124 Rev. W. D. Conybeare on M. de Beaumont's Theory 



transition chain of Scotland, called the Lead Hills, which is 

 continued on the Irish coast by the transition ranges of Down ; 

 of the primitive chain of the Grampians, continued in Ireland 

 by the lines of the Derry mountains, &c, ; and of the principal 

 undulations of the Grampians, as evidenced by the direction 

 of the great depression which affords a line for the Caledonian 

 canal. 



Much of this process of elevation appears to have been like 

 the general elevation of the English strata, gradual and gende; 

 at the same time that it ranges exactly parallel to many lines 

 of disturbance which have been evidently violent, and pro- 

 duced by sudden convulsions limited to definite single pe- 

 riods. This general elevation clearly continued to act through 

 the tertiary period, because in the Irish portion we see the 

 terminal escarpments of the chalk and of the incumbent 

 ridges of basalt conforming to these general lines. The dis- 

 turbances effected in the oolitic strata of Scotland, near their 

 contact with the granitic chains of Sutherland, are obviously 

 of indefinite age. We shall notice them, therefore, more at 

 length when speaking of the disturbances generally affecting 

 the oolites, and only mention them here to state that we have 

 no clear evidence which negatives the supposition that they 

 may have taken place even as late as the tertiary period. 



Supplement to II. Disturbances during the period between 

 the age of the tertiary formations, and that of the new red sand- 

 stone. — Elie de Beaumont has distinguished four difftjrent 

 epochs of disturbance during this period: 1. that of the Rhe- 

 nish system affecting the rothetodte and all the substrata ; 2. 

 that of La Vendee and Morvan, to extending the muschelkalk ; 

 3. that of the Erzegebirge, the Cote d'Or and Mount Pilate, 

 including the oolites; and 4. that of the Pyrenees and Appen- 

 nines, which has also disturbed the cretaceous formations. 



Our own island, however, affords us few well marked ex- 

 amples of disturbance during this period, and these scarcely 

 ever afford us sufficient evidence to pronounce on their exact 

 aera ; so that we must as yet treat of this part of our subject 

 with a much more vague generalitj^ > 



In Yorkshire, indeed, in examining the stratification beneath 

 the cretaceous Wolds, we discover that the oolitic series is 

 unconformably arranged, exhibiting a convex curvature and 

 anticlinal line beneath the absolutely horizontal line of junc- 

 tion of the superimposed chalk ; but here the curvature is very 

 gentle, and no signs of violent disturbance are exhibited : this 

 anticlinal line appears to range nearly E. and W. As the chalk 

 and its greensanrls also at the S. W. extremity in Dorsetshire, 

 overlie the edges of the inferior rocks as far as the red marie, we 



