112 THE GEOLOGY OF BltlUPOltT. 



Let us now turn to the section furnished by these Cliffs along 

 our coast.* At Pinney Bay, two miles west of Lyme Regis, we 

 have an example of No. 1, White Lias, which, properly speaking, 

 is not Lias at all, but belongs to the Rhaetic beds which occur 

 between the Lias and the previous period of New Red Sandstone. 

 Over this comes the Lower Lias, first the celebrated (2) Blue 

 Lias, about 100ft. thick, containing the limestone which is so 

 valuable for cement. Some of the fossils which have made Lyme 

 Regis famous were discovered in this bed, but more above the 

 "Table Ledge," a pale grey band of Limestone which extends 

 between the Blue Lias and a bed (3), of Dark Clay and Shale, 

 180ft. thick. These beds we shall see only in the distance 

 to-morrow. They contain considerable quantities of Iron Pyrites, 

 which have been worked for the manufacture of sulphuric acid. 

 Their decomposition has sometimes given rise to spontaneous 

 combustion. " In August, 1751, after very hot weather, followed 

 by rain, the Lias cliffs at one spot began to smoke and soon 

 afterwards to burn with a visible flame." t Next comes (4) the 

 Pale Grey Marl, 80ft. thick, which constitutes the Belemnite 

 Bed. These are thrown down by a fault at the foot of Golden 

 Cap, but may be visited there at low tide ; and I hope we 

 shall have a good opportunity of examining this place to-morrow. 

 The stratum is " capped with a thin bed of Pale Grey Limestone, 

 known as the Belemnite Stone, which yields Ammonites Henleyii," 

 as well as a profusion of Belemnites, in some of which the ink-bag 

 has been found containing sepia with which sketches have been 

 drawn. It is this stone bed which must be sought for under 

 Golden Cap in places where the sea has washed away the softer 

 superincumbent clay and left exposed considerable platforms of the 

 stone. It is succeeded by (5) the Green Ammonite Bed, about 

 100ft. of dark bluish Grey Clay, which is now reckoned the 

 highest stratum of the Lower Lias. It takes its name from the 



* See woodcut, p. 113, taken from a block kindly lent l>y Mr. H. B. 

 WoodwutL 



t II. 13. Woodward, Geology of Enyhuul and Wales, p. 270. 



