Vol.51.] RADIOLARIAN ROCKS IN THE LOWER CULM MEASURES. 659 



thickness until on the left side of the Bhine near Aix-la-Chapelle 

 it replaces the Culm Beds altogether. Of the 29 species of fossils 

 recorded by Dr. Kayser from the Culm of Aprath, 11 are found 

 in our Culm Series, and 9 of these in the Badiolarian Beds. The 

 correspondence is further shown by the occurrence at Aprath of 5 

 species of Phillipsia which are nearly related to the forms of this 

 genus in the Badiolarian Beds of North Devon. So far as we are 

 aware, no radiolaria have as yet been described from the Kiesel- 

 schiefer of Aprath. 



Dr. Holzapfel states l that the Culm Beds at Herborn in Nassau 

 consist of Thonschiefer with Posidonomya Becheri, below which is 

 a thin zone of Kieselschiefer resting on diabase, and this in some 

 places is succeeded by black or dark limestones with P. Becheri. 

 Holzapfel considers that the Posidonornya-shales are in character 

 nearer to the Devonian than to the Carboniferous Limestone, 

 especially in the abundance of cephalopods and the rarity of corals 

 and brachiopods, and that they indicate a deep-water formation. 

 Dr. von Koenen 2 has described 44 species of fossils from the Herborn 

 Culm, but there are only 7 identical with the English beds. 



The Culm Series in the Upper Harz is shown by A. von Groddeck 3 

 to consist of an upper series of conglomerates, shales, and grauwacke, 

 known as the Grunder Grauwacke and the Clausthaler Grauwacke ; 

 below these are beds of Thonschiefer with Posidonomya Becheri and 

 Goniatites crenistria, which rest on basal beds of Kieselschiefer. 4 



Prom this lowest division of the Culm near Clausthal, Lautenthal, 

 and Lerbach, in the Upper Harz, in beds of adinole, wetzschiefer, 

 and kieselschiefer, or lydite, Dr. Biist 5 has described a large 

 number of radiolaria, showing that, like the Culm Badiolarian Beds 

 in this country, these rocks are mainly composed of siliceous 

 organisms. So far as comparison is possible the forms from the 

 Harz mostly belong to the same genera, and probably many are 

 specifically identical with those in the corresponding beds in this 

 country. Dr. Biist further mentions 6 that dark carbonaceous beds 

 of kieselschiefer and lydite from the Culm of Hesse, Waldeck, 

 Bussia, and Sicily often consist almost entirely of the shells and 

 spines of radiolaria, with occasionally some sponge-spicules. 



The Culm Measures farther east in Germany — in Thuringia ; 

 between Zwickau and Dresden in Saxony ; in Silesia : and in 

 Moravia — consist principally of conglomerates, sandstones, and 



1 Pal. Abhandl. n. s. vol. i. (1889) p. 3. 



2 Neues Jahrb. fur Mineralogie, etc. 1879, pp. 309-346, & pis. vi.-vii. The 

 list is quoted by Dr. Woodward in ' Carb. Trilobites,' Pal. Soc. 1883-84, p. 63. 



3 Jahrb. d. konigl. Preuss. geol. Landesanst. f. 1882, pp. 44-67. See also 

 Ussher, Proc. Som. Archseol. & Nat. Hist. Soc. vol. xxxviii. (1892) p. 171. 



1 Mr. H. M. Cadell states that the Kieselschiefer, which in the Upper Harz 

 rests conformably on the Upper Devonian, is 100 feet in thickness — this 

 includes the Adinole, Wetzschiefer, G-rauwacke, and some lenticular limestones. 

 The thickness of the Posidonomyenschiefer and Culm Limestone which rests 

 above the Kieselschiefer of the same region is placed at 425 feet. See Proc. 

 Roy. Phys. Soc. Edinb. vol. viii. (1884) p. 216. 



6 ' Palseontographica,' vol. xxxviii. (1892) pp. Ill, 112. e Ibid. p. 122. 



