350 MR. J. E. MAER ON IJMESTONK-ITNOLLS IN [Aug. 1 899, 



leads him to return to the locality known to be rich in fossils, and 

 to avoid the apparently barren region, tends to emphasize the 

 difference between the fossiliferous characters of such limestones 

 as those found north and south of the Craven Faults. The con- 

 sequence is that the fauna of the limestones north of the faults, 

 whose order of succession is well established, is little known, while 

 those of the area where the succession is obscure are well repre- 

 sented in all our principal museums. In 1895, Mr. Garwood and 

 I urged the appointment of a British Association Committee to 

 study the possible zonal distribution of the Carboniferous fossils, 

 and as this Committee has now been appointed and is at work we 

 may expect important results to follow at no distant date. In the 

 meantime, the list of fossils collected from the Lower Scar Lime- 

 stone north of the fault is meagre, and there are practically no 

 fossil-lists of the faunas of the individual limestones that occur 

 between the top of the Lower Scar Limestone and the base of the 

 Millstone Grit. I have been led to make these remarks, because I 

 do not feel that it has been proved that the Shales-with-limestones 

 and the Pendleside Limestone south of the faults are necessarily the 

 equivalents of portions of the Lower Scar Limestone Series on the 

 north. 



I believe, however, that one point is clear : namely, that the 

 fauna of the knolls immediately under the Millstone Grit escarp- 

 ment at Cracoe is identical with that of the knolls by the stream 

 above Scaleber Force at Settle. Individuals of species after species 

 may be hammered out of the limestones of one of the knolls near 

 Scaleber identical with those found on the flanks of Stebden knoll 

 near Cracoe. This is a matter of considerable importance, because 

 in each case the limestone that furnishes the fossils is separated from 

 the Millstone Grit by a single deposit of shales, and there is no fault 

 between the limestones, shales, and grits. If this be so, some of 

 the limestones of the knolls, which are referred by Mr. Tiddeman 

 to the Pendleside Limestone, may well be equivalent to the Upper 

 Scar Limestone of the district north of the fault : in that case the 

 lithological characters of the divisions in the two areas would coincide 

 more closely than if the classification adopted by Mr. Tiddeman were 

 correct. We should have : — 



South Side. North Side. ' 



Millstone Grit. Millstone Grit. 



Bowland Shales. Shales above Upper Scar Limestone. 



Pendleside Limestone. Upper Scar Limestone. 



Shales-with-limestones. Yoredale Shales with limestones. 



Clitheroe Limestone. Lower Scar Limestone. 



Another point requires consideration. If my interpretation of 

 knoll-structure be correct, it is not always necessary that one 

 limestone be repeated upon itself. In some instances, at any rate, 

 two or three limestones might compose a knoll, portions being thrust 

 through the intervening shale, in which case a mingled fauna might 

 exist in the knolls. This cannot be ascertained until we are placed 



