C. LAPWOKTH ON THE MOFFAT SERIES. 



337 





the age of the Hartfell beds, though less perfect than that obtain- 

 able with respect to the underlying division, nevertheless places it 

 beyond a doubt that they stand in the place of some of the Bala 

 beds of Siluria. 



(c) Loiver Llandovery. 



The Lower Llandovery rocks of Wales, in which the fossils of the 

 third division of the Moffat Series might be expected to occur, have 

 not as yet been thoroughly searched for Graptolites ; nor has a single 

 species of the Birkhill fauna been hitherto recorded from any of 

 the Silurians of the principality. 



In the Lake- district, however, the Coniston Mudstone, which 

 occupies a corresponding stratigraphical position above the repre- 

 sentatives of the Bala Limestone, is crowded with Graptolites. At 

 Skelgill and Knock it yields the following Birkhill forms * : — 



Rastrites hybridus (Lapw.). 



peregrinus {Hall). 



distans (Lapw.). 



Monograptus turriculatus (Barr.). 



Halli (Barr.). 



cyphus (Lapw.). 



communis (Lapw.). 



fhnbriatus (Nich.). 



lobiferus (M'Coy). 



Hisingeri (Carr.). 



gregarius (Lapw.). 



Monograptus attenuatus (Lapw.). 



spiralis (Gein.). 



tenuis (PortlJc.). 



argutus (Lapw.). 



Diplograptus vesiculosus (Nich.) 



tamariscus (Nich.). 



Hughesi (Nich.). 



sinuatus (Nich.). 



folium (His.). 



Retiolites perlatus (Nich.). 

 Climacograptus normalis (Lapw.). 



It is needless to insist upon the precise agreement of this fauna 

 with that of the Scottish deposit in question. 



Nor is this agreement less striking when the comparison is made 

 with the faunas of the Graptolitiferous Llandoveries of the continent 

 of Europe. It will be seen from the Table inserted in my brief 

 memoir on the Scottish Monograptidoe (Geol. Mag., Dec. 1876) that 

 the Kieselschiefer of Thuringia, placed by Murchison and others at 

 the junction of the two Silurians, afford almost all the Birkhill 

 fossils, and that many of them are found in the " Colonies" which 

 bridge over the palseontological gap between the Lower and Upper 

 Silurians of Bohemia. 



In the M.-lobiferus beds, which form the inferior division of Dr. 

 Linnarsson's Upper Graptolite Schists and overlie every thing in 

 Sweden to which the name Bala can be applied, the strictly Birk- 

 hill assemblage occurs which is given below f: — 



Rastrites maximus (Carr.). 



peregrinus (Barr.). 



Monograptus lobiferus (MCoy). 



Hisingeri (Carr.). 



spiralis (Gein.). 



triangulatus (Harkn.). 



Sandersoni (Lapw.). 



spinigerus (Nich.). 



Monograptus runcinatus (Lapw.). 



gregarius (Lapw.). 



Diplograptus folium (His.). 



tamariscus (Nich.). 



modestus (Lapw.). 



cometa (Geinitz). 



Climacograptus scalaris (His.). 

 Retiolites perlatus (Nich.). 



Not one of these species descends into the underlying limestones 



* Nicholson, Quart. Journ. Geol. Soc. vol. xxiv. pis. xix., xx., &c. 

 t Linnarsson (Collection). See also Tornquist, CEfvers. af K. Vet.-Akad. 

 Forhandl. 1874, no. 4, p. 26. 



