piiocEEDmas or geological soctettes. 



69 



places are met vrith. under Permian and Trias deposits mneli nearer tlie 

 surface than was previousl}^ suspected, and vrliere the upper rocks gave no 

 evidence of their proximity. The above bore has proved bej^ond doubt 

 that a band of coal-measures lies under the south of Chorlton-on-Medlock, 

 and possibly extends to Heaton JN'orris, being probably brought up by the 

 great Pendleton fault, which most likely passes through the south of Man- 

 chester and joins the fault seen near the railway station at Heaton Norris 

 previously alluded to. 



In the fourth section, at Ordsal, Messrs. Worrall found the Trias beds 

 four hundred and sixty feet in thickness without going through them. At 

 the bottom of the bore the water became so salt that they discontinued the 

 work, it being no longer fit for dyeing and such-like purposes. This is the 

 first instance, to the author's knowledge, where salt water has been met 

 with in the Trias near Manchester. 



The fifth and sixth sections were at Skillaw Clough and Bentley Brook, 

 to the north of the Newburgh station on the Manchester and Southport 

 railway. These were some time since discovered hj Mr. E. Hull, of the 

 Greological Survey, and described shortly by that gentleman in the sheet 

 explaining the map of the district. Further particulars were given of the 

 details of both sections, and an analysis of the limestone was produced, 

 which showed it to differ in its chemical characters from the thin ribbon - 

 bands found in the Permian marls near Manchester, Patricroft, Astley, 

 and Leigh ; it was very like the yellow magnesian limestone found at 

 Stank, in Furness, JSTorth Lancashire. Probably it might prove to be a 

 different bed, and more like the great central deposit of magnesian lime- 

 stone of Yorkshire than the thin beds previously alluded to. 



December 24f/^ 1861. — J. P. Joule, LL.D., President, in the chair. Mr. 

 Binne}'^ stated that many years since he had communicated to the Society a 

 description of some markings on the surface of the Kerridge flags. He 

 afterwards published, in Vol. X (New Series) of the Memoirs, a Paper on 

 similar markings, found in the Upholland flags, near Wigan, and attributed 

 then to the burrowing of an animal similar to the common lug-worm of 

 our coast, Xhe Arenicola piscatorum. Similar holes have since been found 

 in rocks of various ages, from the Cambrian upwards. 



The position of the Kerridge flags is, probably, one of the best ascer- 

 tained in whole coal-field. It is in the lower division above the millstoDe 

 grit. In the lower coal-field there are two main beds of flagstones : the first, 

 or lower, the Eochdale series, under the " rough rock ;" and the upper, or 

 TJphoUand or Kerridge series, above the same rock, the chief workable beds 

 of the lower coal-field of Eochdale and other districts, often termed the 

 " mountain mines," lying midway between these two flag-deposits. This 

 series of coal is now, and has been for many year^, wrought under the 

 Kerridge, flags so as prove beyond doubt the position of the latter. Some 

 discussions have lately taken place at Macclesfield as to whether the Ker- 

 ridge beds were Permian or Carboniferous. No one who ever saw Per- 

 mian beds, could ever for one moment suppose Kerridge flags to belong to 

 those strata. It is possible that Permian beds may exist in the low dis- 

 trict lying between Kerridge and Macclesfield, as they have been met with 

 at Hug Bridge on the south, and Norbury Brook on the north, but up to 

 this time they have not been proved to be there. 



Considerable interest has been excited by the discovery of what were 

 supposed to be the foot-marks of some animals on the surface of the flags. 

 He had been induced to make two journeys to Kerridge for the purpose 

 of examining them ; but although plenty of worm-holes and ripple-marks 

 are to be found on the surface of the Kerridge flags, as yet he had seen no 

 tracks of animals upon them. 



