THE BASAL ROCK-GKOUPS OF SHKOPSHIRE 113 



grit (" Cambrian •') is shown as squeezed into the slates ("Monian") 

 so as to be nearly conformable. There is in truth no unconformity 

 whatsoever. The slate, it is true, is somewhat abruptly succeeded 

 by the grit, which is ver}^' massive and shows little clear bedding ; 

 but a conformable passage between the two is apparent without any 

 very critical observation. The reading of the section is represented 

 in fig. 1, below, and my note-book supplies the following par- 

 ticulars : — 



Approaching the section from the east, we pass alternations of 

 purple slates and grits. At Prof. Blake's " junction," we have, on 

 the east side, purple slaty beds interlaminated with seams of purple 

 grit, both slates and grits being rather micaceous. On the west 

 side is a bed of the grit, which appears to have been a little squeezed 

 into the slate, so that here and there a trivial unconformity between 



Pig. 1. — Section at NarnelCs Rock. 



£.S.E. W.KW. 



\ . Junction of Prof. Blake's '• Monian" witli his " Cambrian." 

 c. Conglomerate, with flakes of sbale. 

 ^. Shaly and slatj- beds. 

 y. Grit. 



the two beds is apparent. A seam of slaty rock overlies the jQrst 

 grit-band. A few yards farther on is a thin bed of conglomerate. 

 The included pebbles are largely of quartz, but there also occur 

 numerous thin flakes of purple shale, and these lie flat in the plane 

 of the seam. A little farther west there appears a band of thin- 

 bedded grit, with abundant mica on the lamination-surfaces. These 

 three beds — slate, conglomerate, and laminated grit — have the same 

 dip (N.W. by W. at a high angle) as the underlying " Monian." 

 The alleged unconformity is thus absolutely disproved, so far as this 

 fiection is concerned. 



All the grit in the crags to the west is apparently massive, and as 

 there are no exposures in the slopes below the section, there is an 

 appearance of what Prof. Blake calls a " horizontal crag." That 

 this grit is not an outlier, but an integral part of a regular series, 

 is further evident from the fict that it can be followed on the 

 strike into Callow Hollow on the south, and into Lightspout Hollow 

 on the north, to saj- nothing of more distant localities. 



It seems to have been supposed * that the flakes of purple shale 

 found in the upper series are derived f ragments from an earlier 

 formation. This argument, if it were taken into consideration, 



* Op. cif. pp. 302, 393. 



