STRATIGRAPHICAL GEOLOGY. 447 



several geologists, amongst others by Krejci, Lipold, Marr, 

 Lapwortji, and a controversy began which continued from 

 1859 to 1 88 1. The contention of Barrande's opponents was 

 that the colonies had been brought into their apparently 

 paradoxical position by tectonic disturbances of the rocks, 

 whereby certain layers of rock had been sliced and fragmented, 

 and slices of them had been carried into new positions during 

 the crust-movements. Several geologists differed from Barrande 

 about the age which he had ascribed to some of the Bohemian 

 deposits. Marr thought the Azoic stage B of Barrande repre- 

 sented a Cambrian deposit, and Emmanuel Kayser, judging 

 from his own study of the oldest Devonian deposits in the Harz 

 mountains, thought Barrande's stages F, G, and H were not of 

 Upper Silurian age, but belonged to the Devonian system. 

 The Harz fossils, which had been described by Beyrich and 

 Lessen as a " Hercynian stage," closely resembled these fossils 

 in the upper horizons of the Silurian series in Bohemia, and 

 Kayser removed this fauna altogether from the Silurian 

 sequence and described it as Lowest Devonian. Many of 

 the best authorities on Palaeozoic faunas have subsequently 

 corroborated Kayser regarding the Devonian type of the fauna 

 in Barrande's higher stages. 



The Silurian system in Sweden was sub-divided palaeonto- 

 logically by Angelin in 1854 into eight groups, the lowest of 

 which he called Regio I. Fucoidarum, and the succeeding 

 seven stages also received distinctive names according to the 

 typical Trilobite genus. All the Trilobite genera occurring in 

 Sweden were described in Angelin's works (1852 and 1854). 

 The more recent memoirs by Lindstrb'm, Linnarson, Nathorst, 

 Tullberg, and Holm have supplemented and improved 

 Angelin's researches. 



The Norwegian Palaeozoic deposits, described in the early 

 years of the nineteenth century by Leopold von Buch, as 

 well as by Hausmann and Keilhau, were revised by Kjerulf 

 (1855-57) and arranged in palaeontological sequence after the 

 model of the British " Silurian " district. Newer memoirs have 

 been contributed by Broegger (1882) and Kiar (1897). 



The Palaeozoic deposits in the Baltic Sea provinces of Russia 

 were first examined by Strangways (1819), and were made the 

 subject of special researches by Pander and Kutorga. Murchi- 

 son recognised Silurian and Devonian strata during his visit to 

 that area, and Pander afterwards gave excellent descriptions of 



