Vol. 57.] THE PENDLESIDE GEOUP AT PENDLE HILL, ETC. 389 



established a Millstone Grit Series if he had not thought it a sacred 

 duty to make the succession of rocks in those areas conform to 

 a typical section, the extremely local character of which had not been 

 recognized ? In North Staffordshire and Derbyshire it is absolutely 

 impossible to establish a satisfactory stratigraphical base or top for 

 the Millstone Grit Series, and North Staffordshire and Derbyshire 

 are areas where the grits are strongly developed. 



On the other hand, palaeontology with no uncertain hand points 

 out the main and secondary lines of subdivisions, and clears away 

 all the stratigraphical difficulties which have heretofore hindered 

 the correct correlation of the different types of Carboniferous rocks 

 in Great Britain and Ireland. 



lY. Physical Geogkaphy. (See map, fig. 1, p. 376.) 



The peculiarly regular and gradual change from north to south 

 in the character of the Lower Carboniferous rocks of Great Britain 

 points clearly to a geographical factor : that factor is the close 

 proximity to, and the influence of, land. 



Despite the physiographical maps of this period published by 

 Prof. Hull, the late Prof. Green, and Mr. Jukes-Browne, in which this 

 proposition is distinctly laid down, the deductions from the facts on 

 which these maps are based have not been used to elucidate the 

 change in character of the Carboniferous rocks. On the one hand, 

 contemporaneous faults of considerable throw, and on the other, 

 subsequent highly complicated and extensive local movements, 

 have been advanced to explain changes which are entirely due to 

 alterations of depth and coast-line. 



The maps just quoted all agree in placing a large continent 

 to the north and east (which is the main factor), and a more or 

 less continuous barrier of older rocks extending from Wicklow to 

 Leicester : but they differ in many details, which are of no great im- 

 portance and need not be discussed here. The central ridge, however, 

 was practically of no great extent from north to south, and is 

 unlikely to have furnished any very considerable amount of sedi- 

 mentary material. Indeed, it is probable that here was a long line 

 of high cliffs, and the deepest Avater of the Carboniferous sea in 

 Britain was north of this elongated neck of land. 



Practically no Carboniferous rocks are to be found north of a line 

 joining the Firths of Tay and Clyde, and therefore somewhere along 

 that parallel must have been the line of the old Carboniferous shore. 

 The lithological character of the Calciferous Sandstone Series, its 

 grits, its shales, with many freshwater genera at several horizons, 

 and its only occasional marine bands, all point to such a condition — 

 proximity to land. Sandstone and shale-deposits denote the wear 

 and tear of land-surfaces, and demonstrate the fact that they were 

 laid down within the fan-shaped area which received the solid matters 

 brought down by any large river. 



The whole of the Carboniferous Limestone Series of Scotland 

 corresponds very closely with the alternating series of the Yoredale 



