528 MISS G. L. ELLES ON THE GRAPTOLITE [Aug. 1 898, 



of liis' Lower Graptolite-Shales ' ( = PhyUograptus-ski&eT). This 

 zone is succeeded by a series of Graptolite-mudstones, divided by 

 bim into several zones, which form the lower part of his ' Middle 

 Graptolite-Shales ' {Dicellogra2:)tus-ski&er). 



The fauna of this zone of Phyllograptus cf. tgpus, Hall, is 

 undoubtedly present in the Skiddaw Slates, almost every species 

 which occurs in it in Sweden being also found in the Lake District, 

 such for instance as Bidymograptus gihherulus^ jSTich., D. patidiis 

 (Hall), B. hifldus (Hall), Azygograptus suecicus, Moberg, Phyllo- 

 graptus typus^ Hall, etc., which are all found associated on the 

 same slabs of Skiddaw Slate. 



The minuter zones of the Phyllograptus-skif^eT which lie below 

 the Orthocerkalk are well developed in Yestrogothia, where they 

 have been worked out by Dr. Tornquist (of Lund). He very kindly 

 communicated to me privately the results of his work, but its 

 pubKcation must be awaited before a detailed comparison with the 

 Skiddaw Slates can be made. It may be noted that I have reason 

 to believe that all the zones are represented in the Skiddaw Slates, 

 and are present at Barf and probably also at other localities. 



The fossils collected from Oiiterside, Thornship Beck, Glender- 

 amakin Eiver, and other places seem to indicate the presence of 

 rather higher beds than those at Barf, Randal Crag, etc. The 

 noticeable feature in the fauna from these localities is the abundance 

 of Diplograptids, and the presence of Didymograptids belonging to 

 the ' tuning-fork ' group. I consider these to be the equivalents of 

 the Ellergill Beds of the Cross Fell lulier. 



These Ellergill Beds, in addition to numerous Diplograptidse, have 

 yielded Placoparia, a trilobite which has also been found at 

 Outerside ; this indicates that the beds are of Llanvirn age, and 

 the overlying Milburn Beds must be newer, and may possibly be 

 referred to the lower part of the Llandeilo. Unfortunately, the 

 fauna which they have yielded at present is scanty, but it does not 

 in any way go against this view. 



The Ellergill Beds I believe to be represented by the two lowest 

 zones of the Swedish Bicellograj)tus-iik\&er, or possibly even by more 

 zones than these. It is possible that there exists in the Lake 

 District a series of fossiliferous mudstones representing all the 

 beds up to the Glenkiln zone of Coenograptus gracilis (Hall), but 

 whether a detailed zonal classification of these beds by means of 

 their graptolites will ever be feasible it is very hard to say. 



A portion of the Skiddaw Slates is certainly represented by the 

 Bennane Shales of Southern Scotland ; these beds probably repre- 

 sent the whole of what I have called ' Middle Skiddaw Slates ' in the 

 appended table (III, p. 530). 



The divisions of the Skiddaw Slates which I have adopted are 

 based entirely on palaeontological evidence ; the separation of the 

 Lower Skiddaw Slates is sufficiently obvious, but it must be noted 

 that it does not correspond to Mcholson's ' Lower Skiddaw Slates.' 

 The threefold division of the Middle Skiddaw Slates is based upon 

 the following facts : — (1) That I have found Tetragraptus Bigshyi 



