ON THE STOCKDALE SHALES. 677 



number of interstratified greyish-black Graptolitic shales, the whole 

 attaining a thickness of about 15 feet. There are two important 

 Graptolitic bands 2 feet 8 inches apart, and each about 3 inches 

 thick, and a number of minor ones. Many of the species are limited 

 to one or two bands ; but it would be difficult to subdivide this group, 

 though it may be noted that Hetiolites Geinitzianus occurs chiefly in 

 the higher bands. The Graptolitic beds are usually weathered to a 

 buff colour, on which, as in the M.-turriculatus zone, the Graptolites 

 occur as brown stains. The fossils are : — 



Monograptus crispus, Lapi 



exiguus, Nich. 



pandus, Lapw. 



discus, Tornq. 



griestonensis, Nicol. 



Monograptus Hisingeri, Carr, 

 Cyi'tograptus Grrayaj, Lwpw, 



• ? spiralis, Gein. 



Petalograptus palmeus, Barr. 

 Eetiohtes Geinitzianus, Barr, 



The four species at the top of the list and the Retiolites are 

 extremely abundant. Eor a long time we were disposed to adopt 

 M. exiguus, Nich., as the type-fossil of the zone ; but as M. crispus, 

 Lapw., appears to be more abundant, we have decided to speak of it 

 as the Zone of Monograptus crispus, including with it the 19 feet 

 of pale shales which occur below it, and also the succeeding 10 feet 

 of pale shales devoid of Graptolites which occur between these black 

 shales and the band next to be described. These pale shales 

 contain another monoclinal fold, also apparently unaccompanied by 

 any fault. 



B6. Upper Browgill Beds. 



The deposit which we take as the base of the Upper Browgill Beds 

 occurs at the extreme summit of the rake, and above it the moorland 

 is reached with few exposures ; but the deficiency of sections can be 

 easily made up by an examination of the beds of the main stream 

 of Stockdale. 



The base of these Upper Beds, B& 1, consists of a calcareous 

 development of the pale shales seven feet six inches in thickness. 

 We find a lower blue calcareous band with weathered calcareous 

 nodules like those of the glaber- and punctatus-zoiies of Skelgill, 

 2 feet 6 inches thick, separated from an upper band of similar rock, 

 one foot thick, by about four feet of pale shales. We have dis- 

 covered no fossils in these beds, and indeed, with the exception of a 

 few undeterminable Brachiopods, have obtained no fossils in any 

 locality from the Upper Browgill Beds, though we have searched for 

 them carefully. We feel convinced, however, that some will 

 eventually be found. Before quitting this section it may be noted 

 that we have measured 65 feet of shales and subordinate grits 

 belonging to the Lower Browgill Beds. 



Eeturning to the Stockdale Beck, we can complete the section, 

 which, indeed, is here so much more perfect than that of Browgill that 

 we should certainly have adopted the name Stockdale Shales for the 

 upper group, if it had not been previously used for the whole series. 

 The two zones we have described as forming the Lower Browgill Beds 

 of the rake are also seen in the main beck, where the Graptolitic shales 



