GEOLOGY 



have exerted a powerful influence on the ancient inhabitants, appearing 

 to them as something above the common and therefore fit burial places for 

 their chiefs. Many of the stream-cut gorges are strikingly deep and 

 gloomy ; while elsewhere the rocks have been opened out into curious 

 chasms, such as the impressive cleft of Ludchurch 100 yards long, 30 to 

 40 feet deep, and 6 to i o feet wide south of the Castle Cliff Rocks. 



The Millstone Grits are arranged in lesser or greater synclinal folds 

 completely or partially surrounding the coalfields; frequently, as in the 

 small elongated trough of Goldsitch Moss with perfect symmetry. 

 Denudation has removed vast masses of material, thus severing the outcrops 

 and forming detached areas, of which the outlier of the Third or Roaches 

 Grit on the summit of Sheen Hill is the most remote. 



Seams of coal which are rare in the Pendleside Series become of 

 greater frequency and are usually present a few feet above or lying 

 directly on the grit bands. The most persistent is a seam above the 

 Third Grit, which was formerly worked to a considerable extent in 

 the Roaches and Ipstones areas. Another seam, known as the Feather 

 Edge Coal, lying above the First Grit, also proved to be workable around 

 parts of the Goldsitch Moss Coalfield, though the seam should more 

 properly be included in the Coal-measures. The commercial value of 

 the sub-division however mainly consists in the fairly good quality of the 

 building stones afforded by the First and Third Grits, both of them, 

 but especially the latter, being extensively quarried. 



The fossils of the ' grits ' consist of the remains of plants Ca/amifes, 

 Lepidodendron. Plant remains are also met with in the shales, but 

 the most interesting fossils are the marine organisms Ptennopecten papy- 

 raceus, Posidoniella /&vis, Goniatites which occur in abundance in certain 

 dark bands of impure limestone lying in muddy shales between the First 

 and Third Grits, of which the banks of the Trent to the east of Knypers- 

 ley Reservoir afford an excellent section. 



COAL MEASURES 



The detritus-bearing currents now swift, now gentle which de- 

 posited the grits and shales of the Pendleside Series and Millstone Grits 

 continued to carry their burden seaward long after the First Grit was laid 

 down. The pauses in sedimentation however became more prolonged, 

 the sea was frequently excluded, and the floor, owing to constant 

 deposition aided by local elevation, was even raised above sea-level. The 

 lower portion of the Coal-measure formation, with its great thicknesses 

 of shales, clays, sandstone and intercalated coal seams, ironstones and 

 marine bands, demands some such varied conditions of origin. During 

 the later stages of the period the pauses became brief and a large body of 

 sediment was deposited, but now under new conditions. A land-locked 

 area appears to have been formed upon whose continuously sinking 

 floor mainly red sediments thickly accumulated. The end of the story 

 however is not known ; the record is lost or buried deep under the 

 overlying Triassic rocks with their history of a new order of events. 



ii 



