562 Rev. D; Williams on Trap Rock in the Mountain Limestone of BleadonHill. 



For the principal details represented in the accompanying woodcut I am in- 

 debted to Mr. Peniston the resident engineer, who had the kindness to prepare for 

 me a graphic representation of the whole cutting, but of which only a portion is 

 here given. 



0, Trap, apparently substituted for the originally continuous limestone, by slow fusion and conversion. 



i, Mountain limestone, showing remarkably uneven surfaces and ragged edges at its immediate contact with the trap. 



e. Blue lias, overlying black shales with the Watchet and Aust Cliff bone-bed ; grey passage marls below. 



d, Dolomitic hmestone, resting unconformably on the successively outcropping steps of the mountain limestone. 



e, Upper gypseous red marls of the new red sandstone. 



