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University of California Publications in Geology [Vol. 11 



larian cherts of England which occur at the same horizon. These 

 cherts have been described by Caddell 75 in the following words : 



The kieselsehiefer, or lydian stone of the Harz, is a compact, very hard, in- 

 fusible, hornstone-like siliceous rock, with splintery fracture and dark color, and 

 is impregnated with carbonaceous material and iron oxide. It occurs in beds 

 made up of layers from 1 to 4 inches in thickness, and is traversed by numerous 

 joints, and veined with quartz. . . . 



The Kieselsehiefer beds are, in almost all the cases I have seen, intensely 

 crumpled, and bent into sharply-defined folds, in a way which shows them to have 

 been quite plastic at the time of their contortion. 



Associated with these beds are ordinary shales and arkose sand- 

 stones. Adinoles occur in association with the cherts. These are an 

 intimate mixture of quartz and albite, containing sometimes as much 

 as ten per cent of soda. They resemble the hornstone very closely 

 but are distinguishable by their greater fusibility. 



OTHER OCCURRENCES IN CENTRAL EUROPE 

 In addition to the occurrences above listed there are other radio- 

 larian cherts of Paleozoic age which will not be described in detail 

 here. 



Radiolarian Cherts of Saxony™ — These are intimately associated 

 with clay slates, "alum-slates," graywackes, quartzose sandstones, 

 diabase flows and intrusive diabase. They are of Lower Silurian 

 (Ordovician) age. The cherts and clay slates contain graptolites. 



Rhine Valley. — Wilckens 77 has described radiolarian cherts from 

 the Lower Carboniferous of the Rhine District. 



Rust refers to several other occurrences of radiolarian cherts in 

 central Europe. Cherts of Devonian age occur in Nassau and Hesse. 

 Ordovician kieselsehiefer occur at Rehau in Bayern and at Cabrieres 

 in Languedoc. Carboniferous kieselsehiefer occur near Braunau and 

 Wildungen in Waldeck and in the Bukk Mountains in Hungary. 



"The Harz Mountains, their Geological Structure and History, Roy. Phys. 

 Soc. Edin., vol. 8, p. 217, 1883-85. 



7e Rothpletz, Radiolarien, Diatomaceen und Spharosomatiten in silurischen 

 Kieselsehiefer von Langenstriegis in Sachsen, Zeitschr. d. deut. geol. Ges., 

 sxxii, 447, 1880. 



Rust, op. cit., Palaeontographica, xxxvin, 107, 1891-92. 



" Wilckens, O., Radiolarit im Kulm der Ottendorn-Elsper Doppel-Mulde, 

 Zeitschr. d. deut. geol. Ges., Monatsblatt, 1908, p. 354. 



Cited by Grabau in Principles of Stratigraphy, p. 459. 



