115 



that these beds are lying unconformably on other Carboniferous 

 strata below, is something enormous. And it should not be 

 forgotten that in any given case — such as this of Shawk Beck — 

 the onus J>robandi is entirely on the side of the assertor of the 

 unconformity. 



I may be told, perhaps, that evidence on this head is given by 

 Mr. Kendall in his sheet of vertical sections (PI. xxxiii.) as regards 

 the purple-grey beds of the Coal-field, at least. But it seems to me 

 that an impartial observer of the vertical sections could hardly fail 

 to detect therein at least one point almost decisive in itself against 

 its author's view. Let us accept Mr. Kendall's correlation of the 

 coal-seams, and compare the sections of BuUgill [and Aspatria. 

 We have as a base in each case the Yard Band. Ascending from 

 that horizon we notice (taking Mr. Kendall's own correlation) that 

 a greater thickness of measures intervenes between the Yard and 

 Cannel Bands at Aspatria than at Bullgill. Above the Cannel the 

 Metal Band and the Thirty-inch Band are correlated in the two 

 pits, the greater thickness of the measures at Aspatria being still 

 maintained. Still ascending, the thin coal called the Rattler Band 

 at Bullgill does not appear at Aspatria, though a bed, apparently 

 of black or dark shale, lying a short distance below it, seems to be 

 represented at the latter place, just where it might be expected. 

 Then the Ten Quarters Coal at Bullgill, seems to be naturally 

 represented by a coal styled " Ten Quarters Coal of Bankend Pit," 

 at Aspatria. But Mr. Kendall has not drawn a Une connecting 

 the Ten Quarters Coal at the two places, though the position of 

 that seam at Aspatria is precisely uliere we should expect to see it, 

 considering the thickening of the measures there, and noticing that 

 a line connecting the coal at the two localities would have a 

 direction almost perfectly parallel with those connecting the lower 

 coals. Above the Ten Quarters Coal, a series of coal and shaly 

 beds at Bullgill appears (to me) to be represented by a somewhat 

 thicker series at Aspatria, and a thickish sandstone at Bullgill by 

 another somewhat thicker at Aspatria. Then a not-very-well 

 marked series is seen at both places, and the surface is reached at 

 Aspatria. But at Bullgill a series of beds not (it appears to mej 



