Notice^ of Memoirs — Dr. G. Linnarsson — Grajjtolite Schists. 281 



precede the Lobiferus Schist, the fauna has already appeared, which 

 is most nearly to be compared with that of the Caradoc group. 



In the North of England again we meet with the Graptolites of 

 the Lobiferus Schists in that group of shaly strata called the 

 Coniston Mudstones.^ According to the lists of their fossils given 

 by Harkness and Nicholson, they include a Trilobite fauna having a 

 thoroughly Lower Silurian aspect, and which can best be compared 

 with that of the Trinucleus Schiefer. Till this abnormal relation- 

 ship has been confirmed, the author is of opinion that we ought to 

 be allowed to believe that some mistake has been committed. 



Several of the fossils of the Lobiferus Schist, such as M. lobiferus, 

 M'Coy, M. spiralis, Bastrites peregrinus and Diplograpt. palmeus, are 

 found also in Bohemia, partly in Barrande's Etage Eel, and partly 

 in the Colonies in his Etage D.^ On both stratigraphical and 

 pal^ontological evidences, the author had already paralleled the 

 Lobiferus Schists, in common with the Upper Graptolite Schists, 

 with the Etage Eel. Tornquist, on the contrary, has suggested that 

 the Upper Graptolite Schists are rather contemporaneous with the 

 Colonies.^ This last view is chiefly founded upon the supposed 

 English succession; but now, since this has been more accurately 

 determined, the facts give force, on the other hand, to the author's 

 opinion. It was formerly supposed that the fauna which characterized 

 the Swedish Upper Graptolite Schists belonged to the Llandeilo and 

 Caradoc. It is now proved that they belong to the Middle and 

 Upper Silurian strata. As regards the equivalents of the Lobiferus 

 Schist — the Birkhill Shales and the Coniston Mudstones — the former 

 are believed by Lapworth to belong to the Lower Llandovery ; the 

 latter by Harkness and Nicholson to the Uppermost Bala or Lowest 

 Llandovery. 



The Coniston Flags, which in their strata and fossils may be com- 

 pared with the Eetiolites Schists, are now regarded by English 

 authors as an Upper Silurian formation. In England, therefore, as 

 well as in Sweden and Bohemia, these special Graptolite faunas thus 

 stand in near relation to the Upper Silurian formations. Their 

 appearance in true Lower Silurian formations is, on the contrary, 

 peculiar to Bohemia. The Leptena Limestone, which overlies the 

 Upper Graptolite Schists, can scarcely be mentioned as true Lower 

 Silurian ; while the Brachiopod Schist, which underlies the Lobiferus 

 Schist, has already a far greater Upper Silurian aspect than even the 

 very highest strata of Barrande's Etage D. These last-mentioned 

 beds agree nearest with the lower part of the Trinucleus Schists of 

 Sweden. Naturally, perfect synchronism between the Swedish 

 Upper Graptolite Schists and the Bohemian Etage Eel, can hardly 

 be said to be actually demonstrated. They are, however, at any rate, 



1 See, for example, the list given by Harkness and Nicholson, Quart. Journ, Geol. 

 Soc, London, vol. xxxiii. 1877, p. 473. The Coniston Mudstones are not, as asserted 

 by these authors, equivalent to the whole of the Swedish Upper Graptolite Schists. 

 The Eetiolites Schists are clearly older and are related to the Coniston Flags. 



2 Vide Barrande, Defense des Colonies, 1870, vol. iv. p. 125. „ 



3 Tornquist, Om Siljanstraktens paleozoiskas formationsled, Ofvers. af K. Vet. 

 Akad. Fcirhandl., 1874, Nr. 4, p. 24. 



