Lower, 

 120 to 

 140 feet 



THE JURASSIC SYSTEM 407 



studied by Oppel, Quenstedt (1850-88), Struckmaim (1881), 

 Waagen (1864), and Stuber (1893). Its thickness is here compara- 

 tively small, but most of the zones established in England and 

 France have been recognised, and the general succession of beds is 

 as follows : 



Upper, /Grey marls with Lytoceras jurense. 

 30 feet (Bituminous shales with Posidonomya. 



/"Limestone with Paltopleuroceras spinatum. 

 Middle, Clays with AmaWwus margaritatus. 

 100 feeM Hard marls with Deroceras Davcri. 



^Clays with Rhacoceras ibex and Uptonia Jamesoni. 

 r Clays with Asteroceras obtusum and Oxijnoticeras oxynotum. 

 Bituminous shales and Pentacrinus Beds. 

 Limestones with Oryphcea and Coroniceras Buckla'ndi. 

 Sandstones with Schlotheimia angulata. 

 Limestones with Psiloceras planorbe. 

 .Rhsetic sandstones and shales (20 to 40 feet). 



In Northern Germany there are irregular outcrops of Lias along 

 a tract extending from the Teutoburger Wald eastward through the 

 south to Hanover and Brunswick ; the component beds being very 

 similar to those of Swabia and Franconia. Moreover, it appears to 

 extend northward and north-eastward below the great plains of 

 Hanover and Prussia, for its existence has been proved by a 

 boring at Hermsdorf near Berlin and by another at Kammin in 

 Pomerania. 



2. Sweden 



The Lias recurs on the north side of the Baltic in Scania, where 

 the Rhsetic position has an estuarine facies, consisting of a series 

 of sandstones, shales, and clays with beds of lignitic coal and of 

 clay ironstone ; in fact a " carboniferous " facies, with a thickness 

 of about 300 feet. Plant remains are very abundant, including 

 species of Camptopteris, Lepidopteris, Thaumatopieris, Nilssonia, and 

 Dictyophyllum with many Cycads and some coniferous trees. Over- 

 lying these deposits are shales and sandstones with marine fossils, 

 as well as plant remains, and these appear to represent the zones of 

 Psiloceras planorbe and Coroniceras Bucklandi. In Central Scania 

 to the north-east the Rhaetic Beds have disappeared, and the marine 

 shales are represented by massive sandstones which lie directly on 

 the Archaean rocks and are made up of detritus derived from the 

 latter. 



3. The Alpine Region 



In this region and in the south of Europe generally the Lias 

 assumes a completely different facies from that which prevails in 

 Germany and the north of France, for it passes into a series of 



