Trof. T. Sterry 'Eunt — On Cambrian and Silurian. 455 



greenstone. Above these higher slates there are found in some parts 

 of Gothland, other limestones with Orthoceratites, Trilobites and 

 Corals, the newer limestone strata (a) of Hisinger; the whole over- 

 laid by thin sandstone beds. These higher limestones and sand- 

 stones contain the faima of the Wenlock and Ludlow of England ; 

 while the lower limestones and Graptolitic slates afford Calymene 

 Blumenbachii, Orthis calligramma, and many other species common 

 to the Bala group of North Wales. The alum-slates below these 

 however, contained, according to Hisinger, none of the species then 

 known in British rocks, but in their stead five species of Olenus and 

 two oi Battus (Agnostus). 



In 1854: Angelin published his Palceontologica Scandinavica, part 1, 

 Crustacea formationis transitionis (4to. forty-one plates), in which he 

 divided the series of transition rocks above described by Hisinger 

 into eight parts designated by Eoman numerals, counting from the 

 base. Of these I. was named Regio Fucoidarum, no organic remains 

 other than f ucoids being known therein ; while the remaining seven 

 were named from their characteristic genera of trilobites, which were 

 as follows, in ascending order; certain letters being also used to de- 

 signate the parts : n. (A) Olenus; HI. (B) Conocoryphe; IV. (BC) 

 Ceratopyge; V. (C) Asaphus; VI. (D) Trinucleus; VII. (DE) 

 Harpes; VIII. (E) Cryptonymus. In the Begio Olenorum (II.) was 

 found also the allied genus Paradoxides. With regard to the cha- 

 racteristic genus of Eegio III., the name of Conocoryphe was pro- 

 posed for it by Corda in 1847, as synonymous with Zenker's name 

 of Conocephalus ( Conocephalites) already appropriated to a genus of 

 insects. 



Meanwhile, the similar crustaceans which abound in the' transition 

 rocks of Bohemia had been studied and described by Hawle, Corda 

 and Beyrich, when Barrande began his admirable investigations of 

 this ancient fauna and of its stratigraphical relations. He soon found 

 that beneath the horizon characterized by fossils of the Bala group 

 (Llandeilo and Caradoc) there existed in Bohemia a series of strata 

 distinguished by a remarkable fauna, entirely distinct from anything 

 known in Great Britain, but closely allied to that of the alum-slates 

 of Scandinavia, corresponding to Eegiones II. and III. of Angelin. 

 To this he gave the name of the first or primordial fauna, and to the 

 rocks yielding it that of the Primordial Zone. Besting upon the 

 old gneisses of Bohemia appears a series of crystalline schists de- 

 signated by Barrande as Etage A, overlaid by a series of sandstones 

 and conglomerates, Etage B, upon which repose the fossiliferous 

 argillites of the Primordial Zone or Etage C. The rooks of the Etages 

 A and B were by Barrande regarded as azoic, but in 1861 Fritsch of 

 Prague, after a careful search, discovered in certain thin-bedded 

 sandstones of B the traces of fiUed-up vertical double tubes, which, 

 according to Salter (Mem. Geol. Surv.,vol. iii. p. 243), are probably the 

 marks of Annelides, and are identical with those found in the I'ocks 

 of the Bangor or Longmynd group in Great Britain ; which will be 

 shown to belong to the Primordial Zone. It is, therefore, probable 

 that Etage B, which apparently corresponds to the Kegio Eucoi- 



