216 bulletin: museum of comparative zoology. 



Here the upper Trinucleus shales, also called the Staurocephalus 

 shales, are reported to be very fossiliferous and add Staurocephalus 

 clavifrons, Acidaspis ccntrina, and Phillipsia parabola to the list of 

 species found at Kinnekulle. 



Oeland. 



The Ordovician on Oeland rests on Upper or Middle Cambrian 

 strata and the basal member may be either the Dictyonema shale or 

 the Ceratopyge shale. This has been especially well brought out in 

 an instructive diagram by Fearnsides (59). The most complete 

 section of the "Ceratopyge Region" and Cambrian is shown in south- 

 ern Oeland, where, ignoring subzones, the following strata are found, 



in descending order. 



Ordovician 



Glauconite shale. 

 Ceratopyge limestone. 

 Glauconite shale. 

 Shumardia shale. 

 Dictvonema shale. 



,T /-. 1 • i Peltura hmestone. 



Upper Cambrian w.,, i , 



^'^ [ Olenus shale. 



I Paradoxides forchammeri zone. 

 Middle Cambrian I P. tessini zone. 



[ P. oelandictis zone. 



It has been shown that in passing northward both the Dictyonema 

 and Shumardia shales pinch out, but at the northern end of the section 

 both come in again, the Dictyonema shale being in certain localities 

 replaced by the Obolus conglomerate. At the southern end of the 

 island the Ordovician rests upon the youngest known beds (zone of 

 Peltura scarahoides) of the Upper Cambrian. About midway between 

 the northern and southern ends the Peltura beds disappear and the 

 Ordovician rests for a short distance on the lower part of the Upper 

 Cambrian. From Borgholm for several miles north the Ordovician 

 rests on the next lower zone of the Cambrian, the Paradoxides jorcham- 

 meri zone of the Middle Cambrian. Still further north this gives 

 place to the next lower zone, that of P. tessini. The strata of the 

 Paradoxides tessiu i zone are here sandy, and it is where the Ordovi- 

 cian rests on them that the Obolus conglomerate is developed, thus 

 indicating the local origin of the material in the Lower Ordovician. 



