BALTIC REGION 603 



same is true of the beds referred to the Brachiopod shale at the Kinne- 

 kulle. The abundance of Trinucleus, Staurocephalus, and Dionide in 

 the former and of Dalmanites, Lichas, and Homalonotus in the latter, 

 all genera absent or rare in the East Baltic regions, suggest Atlantic 

 affinities. The same origin probably holds for the G-raptolite fauna of 

 the Upper Graptolite shale (Siluric). 



In Ostergotland, east of Lake Wettern, the Dictyonema shale has a 

 thickness up to 3.5 meters, its base being everywhere a sandstone, which 

 at Vestano is more than 2 meters thick. This has been regarded as the 

 Obolus sandstone by Wiman, though the characteristic fossils have not 

 been found in it. 35 The Ceratopyge limestone seems to be represented 

 by a glauconitic marl. The Orthoceras limestone, quarried since the be- 

 ginning of the nineteenth century, has furnished many of the types of 

 trilobites described by Dalman and comprises in descending order : 



Expansus limestone, greenish to red. 



Gray limestone. 



Heros limestone (with Megalospis heros A.). 



Reddish limestone. 



Planilimbata limestone. 



Underlain by greenish marl and Dictyonema beds, as previously noted. 



Megalaspis heros is characteristic of the Raniceps and Eichwaldi zones 

 of the East Baltic region (B III (3 and B III y), but has not been re- 

 corded from the Expansus zone. The reddish limestone is probably the 

 Limbata limestone, and this would place the break between this bed and 

 the Heros limestone. However, the occurrence of the Expansus limestone 

 higher up suggests some irregularity of interpretation, unless the Heros 

 limestone and the gray limestone above it constitute a part of the Expan- 

 sus zone. The Orthoceras limestone is followed by the Chasmops lime- 

 stone with its lower Echinosphaarites division and the upper with Chas- 

 mops macrourus (Macrourus limestone), and then by Trinucleus shale 

 and Brachiopod shale. 



In Narke (Nerike), north of Lake "Wettern, the break comes above the 

 Planilimbata limestone, which rests on Shumarclia shales (Ceratopyge 

 horizon — ). Beneath this is a glauconitic limestone with phosphatic 

 nodules, which in turn overlies the Peltura zone of the Upper Cambric 

 and cuts out the Dictyonema shales. The succeeding lower gray Ortho- 

 ceras limestone appears to represent the raniceps horizon, B III j3, the 

 Expansus horizon being absent here. 



K Moberg : Silurian of Sweden, p. 150. 



■ XLIV — Bull. Geol. Soc. Am., Vol. 27, 1015 



