162 Dr. Wheelton Hind — The Yoredale Series. 



then declined, as shown by the quantities of shell fragments and 

 rolled fossils it contains. It does not form the extreme top of the 

 limestone, but is itself overlain by a few yards of massive limestone. 

 All the famous fossiliferous localities of Derbyshire and North 

 Staffordshire appear to occur at horizons just immediately above 

 or below this beach. 



The next great exposure of Cai'boniferous Limestone noi'th of 

 Derbyshire is at Clitheroe, and here there is a fine sequence to be 

 seen in the western escarpment of Pendle Hill, at the base of which 

 the limestone is exposed. The top of the hill is formed of grit, 

 formerly called the Yoredale Grit, now recognized by the Geological 

 Survey as a Millstone Grit, older than the Kinderscout, or fourth 

 grit. It is estimated that 2500 feet of shaly beds intervene between 

 the Mountain Limestone at the base, and a series called the Pendle- 

 side Limestone of 850 feet in thickness, which occurs just below 

 a bed of grit called the Lower Yoredale Grit. This bed is not very 

 constant in extent, but whenever it is present it always occupies 

 the same horizon. Mr. Tiddeman describes it in the Memoir on the 

 Burnley Coalfield as follows : " It consists of grits and sandstones, 



with shales and ironstones interbedded In appearance 



they (the sandstones) are often not unlike the Gannister rock of the 

 Lower Coal-measures, though not containing the root beds of that 

 rock ; plant-remains, however, are of common occurrence in them." 



The Lower Yoredale Grit is separated by about 200 feet of shales 

 from the Upper Yoredale Grit, which caps Pendle Hill. These are 

 known as the Boivland Shales, and are important as containing 

 a molluscan fauna of Lower Coal-measure facies — Posidonia,^ 

 OrtJioceras, and Qonintites. From the lists of fossils given at the 

 end of the Burnley Memoir by Mr. Etheridge, it is conclusively 

 shown that the majority of the species found in the Pendleside 

 limestones is common to it and the Carboniferous Limestone 

 below, although the beds are separated by 2500 feet of strata 

 which do not contain a similar fauna. 



The Upper Yoredale Grit of Pendle is supposed to be the 

 equivalent of Farey's Shale Grit of Derbyshire, and with very 

 good reason, on account of the relation which both have to 

 the fourth and fifth, or Kinderscout grits. The upper and lower 

 Yoredale Grits are now known as the Pendleside Grits, and these 

 constitute the base of the Millstone Grit Series of the Geological 

 Survey. From the top of Pendle Hill there is a regular sequence 

 to the Coal-measures of the Burnley Coalfield, and the fourth grit 

 forms a feature of the ground from Hoolster Hill by Mellor Walley 

 Nab and Wiswell Moor to the Nick of Pendle. Succeeding the 

 fourth grit are the Sabden Valley Shales, with Posidonia, Goniatites, 

 Orthoceras, etc. 



1 This name is aljundantly used in Lancashire and Yorkshire for at least two 

 different forms of shells Avhich have been studied by Mr. H. Bolton and myself. 

 I have referred them to Posidonia Icevis and P. minor, Brown, sp., and they form 

 a part of the matter to be published in this year's portion of my Monograph on 

 "The British Carboiiiferous LamLiiibranuhs," by the raliBoutographical Society. 



