147 



If it be granted that the overlap, like the folded strata at 

 Vobster, has been caused by the upheaval of the Mendips, 

 there is another important deduction to be drawn from it 

 It will be observed that there is a wide difference in the 

 extent to which the veins overlap each other ; that while the 

 upper vein of the Kadstock series only overlaps itself to the 

 extent of 120 yards, the lower vein of the same series shows 

 an overlap of 330 yards. Now, had the fault been formed 

 after the whole of the upper series had been deposited, no 

 such difference as this could have existed ; and the inference 

 to be drawn from it is, that the upheaval of the Mendips 

 must either have been accomplished gradually, or by succes- 

 sive steps with long periods intervening. If we suppose the 

 first movement to have occurred shortly after the three lower 

 veins of the upper series had been deposited, and that the 

 movement was subsequently renewed, it would account for the 

 disparity in the amount of overlap, which it seems difficult 

 otherwise to explain. 





S, HATWABD, PRINTER, " BXPRESS" OFFICE, GREEN STREET, BATH. 



