1869.] HULL GEOLOGY OP CHESHIRE. 179 



rock fault," along which the Triassic rocks are brought in on the 

 west. 



It will be observed that along this anticlinal the lower beds of the 

 Yoredale group, immediately overlying the Mountain Limestone, 

 are brought to the surface, this latter rock itself being found at 

 Astbury, at the base of Congleton Edge, but not in the line of the 

 section*. 



As regards the age of this anticlinal, we are, fortunately for our 

 purpose, not left in doubt. Kot far to the eastward is the Permian 

 outlier of Hug Bridge, near Rushton Spencer, where, as already 

 stated, sandstones and marls of Permian age rest immediately on 

 the Yoredale beds. "We have here, therefore, an illustration, similar 

 to that of Clitheroe, in l^orth Lancashire, of disturbances accom- 

 panied by enormous denudation of the Carboniferous rocks at the 

 close of the Carboniferous period, and antecedently to that of the 

 Permian. The amount of denudation in this instance may be thus 

 estimated t : — 



feet. 



[Upper 1000 



Coal-measures < Middle 4000 



[Lower 1000 



Millstone G-rit Several divisions 1000 



Yoredale Series (in part) . Several divisions 2000 



9000 



The easterly prolongation of the anticlinal of the river Dane 

 cannot be very clearly traced, owing to the rearrangement of the 

 Carboniferous beds along the lines of disturbance in a meridional 

 direction (north to south) at the close of the Permian period. As 

 already shown on a former occasion J, the series of foldings along 

 axes ranging from west to east into which the Carboniferous rocks 

 of the North of England were thrown at the close of the Carboni- 

 ferous period have been modified by two subsequent lines of dis- 

 turbance at the close of the Permian and Jurassic periods respec- 

 tively ; but the whole three systems bear a close physical relation- 

 ship in time and direction to each other. In the district bordering 

 the Mountain Limestone of Derbyshire the intersection of these Hues 

 of disturbance, accompanied and followed, as they have been, by 

 several denudations, have complicated the structure of the rocks as 

 it originally existed at the beginning of the Permian period. Hence 

 the difficulty of following out the course of the anticlinal of the 

 Dane eastward ; nevertheless it may, I think, evidently be traced 



* A detailed description of the beds in this district will be found in " The 

 G-eology of the Country around Stockport," &c., by Messrs. Hull and Green. 

 Mem. G-eol. Survey, pp. 69-74. 



t The thickness of the Coal-measures is that ascertained by the Geological 

 Survey as applying to North Staffordshire, which is less than that of Lanca- 

 shire. The thickness of the Millstone Grit and Yoredale beds is that given 

 in the Memoir, on "the Geology of Macclesfield/' &c., above quoted (see p. 85). 

 The above estimates are probably rather under than over the truth. 



I " On the relative Ages of the Physical Peatm-es," &c., suj)ra cit. 

 VOL. XXV. PART I. O 



