230 MR. E. W. BINNEY ON THE PERMIAN BEDS 



elevated before the deposition of the permian and trias beds, 

 but it is evident that the two latter have been raised by the 

 forces which have subsequently elevated the coal-measures, as 

 the partial similarity of the dip in both strata proves. 



The carboniferous strata which ne^ct make their appearance 

 are the red sandstones of Collyhurst and Smedley, and after- 

 wards some measures containing a small coal and a bed of 

 fire-clay. These must be approaching near to the thick coals 

 of the middle field, and are cut off by the Bradford and Ardwick 

 fault, near Mr. David Morris's mill. The permian beds lying 

 in this fault have never been proved, although, no doubt, they 

 lie in it in the same manner, and will be found outcropping to 

 the east, as they do at Droylsden and Beet Bank Bridge. 



In most of the borings made in the neighbourhood of Man- 

 chester, the men employed have frequently classed all the 

 strata gone through, whether arenaceous or argillaceous, as 

 red measures. By these means the red marls will be found to 

 vary very much in thickness, parts of the red sandstones lying- 

 above and below them having been frequently added to them. 

 It was owing to this cause that in my first paper printed in 

 the Transactions of the Manchester Geological Society the 

 thickness of the permian marls and their limestones varied so 

 much — the information respecting the strata having been 

 supplied to me by the different well-sinkers and borers whose 

 names are there given as authorities. Taking the sections of 

 Heaton Mersey, Droylsden, Jericho Clough, Mayfield, 

 Salford, Strangeways, and Newtown for our guide, we shall 

 find that the permian marls will generally be from 120 to 130 

 feet in thickness. As we proceed towards the west we shall 

 find them become thinner, and their accompanying beds of 

 limestone thicker. The limestones in the marls are very un- 

 certain, and seldom found alike even in two bore holes near 

 together. This arises from their occurring in nodular masses 

 rather than continuous beds. 



