576 Correspondence — Mr. A. Strahan. 



7tli, In the Opensliaw boring, the Upper Permian beds are over- 

 laid by 36 feet of true Triassic Bunter beds. 



8th. Looking to the westerly attenuation of these Permian beds, 

 there is no matter of surprise in their comparative thickness at 

 Bedford Leigh and Ashton, and their absence at Winwick and 

 Farnworth. C. E. De Kance, F.G.S., 



Assoc. Inst. C.E. 



THE PERMIAN AND TEIAS. 



Sir, — Permit me to reply to Professor Hull's remarks in your 

 last number on my paper on the so-called Permian Eocks near St= 

 Helens (Geol. Mag. Dec. H. Vol. VHI. 1881, p. 433). 



In this paper I trace the range of these unfossiliferous rocks, 

 showing that they are similar to the Lower Mottled Sandstone of 

 the neighbourhood, and that they thin out without unconformity 

 with this subdivision of the Bunter in those very directions, in 

 which, had they been Permian unconformably overlapped, they 

 might have been expected to develope. They are thus completely 

 separated from those rocks which are referred to by Professor Hull 

 as containing Permian fossils wherever they occur along the border 

 of the Coal-field, and as being unconformably overlain by the New 

 Eed Sandstone. On these grounds I ventured to doubt the correct- 

 ness of their determination as Permian ; Professor Hull merely 

 repeats his belief in its correctness, without offering any explanation 

 of the difficulties which arise in the way of its acceptance. 



I also defined an area (including the village of Winwick) in 

 which I considered Permian to be absent. Professor Hull refers 

 to a shaft at Abram, in which these rocks have been proved, as 

 being near Winwick, and as not being described by me. Abram is 

 nearly six miles from the village of Winwick, and about half that 

 distance from the town of Wigan. It is not only outside the area 

 I defined as being devoid of Permian, but is more distant than the 

 Edgegreen section, to which I alluded for the purpose of showing 

 the nearest known occurrence of these rocks. 



To defend myself from the charge of presumption in forming an 

 opinion opposed to that of the late Mr. Binney and Pi-ofessor Hull, 

 I may mention that since I^Ir. Binney's original examination of this 

 locality and Professor Hull's subsequent survey, when a brewery 

 well and a quarry were the only sources of information, seven shafts 

 at three collieries and three bore-holes have been sunk, all throwing 

 light on the true relations of these rocks, and showing, among other 

 points, that shales equal in thickness to the so-called Permian Marl 

 of St. Helens are not unknown in the Lower Mottled Sandstone of 

 that neighbourhood. My visit was not a flying one, as suggested by 

 Professor Hull ; my repeated examinations of the district resulted 

 from instructions, officially received, to make a detailed survey of 

 the whole area in question. A. Strahan. 



Market Easen, Nov. 11, 1882. 



