BALTIC REGION 607 



Glauconite sand 0.1m. 



Obolus conglomerate 0.15-0.80 m. 



Obolus apollinis Eichw. 



Hiatus — unconformity. 

 Basement beds. 



Weathered granite 0.1 to 0.4 m. 



Fresh granite. 



The beds above the Megalaspis limestone, or the divisions of the 

 Orthoceras limestone in the restricted sense, are well exposed on the shore 

 of the lake just beyond this cutting, and here a good collection of the 

 typical fossils, especially the Orthoceracones, may be obtained. The low- 

 est of these beds, and the one directly succeeding the Limbata limestone, 

 wherever this is found in contact, is the Asaphus limestone with A. ex- 

 pansus Wahl, Vaginoceras vaginatum, and the other species noted above. 

 Most of these species are also found in the Esthonian region, where they 

 are confined to B III and higher beds. Since so many of them are char- 

 acteristic of B III a, the Expansus limestone, and since Asaphus expansus 

 also occurs in this limestone of Siljan Lake, it is evident that the series 

 begins with that division. Thus the divisions B II (3 and B II y found 

 in the Russo-German Baltic provinces are omitted here, and the hiatus 

 in Dalarne falls above the Megalaspis 4 limbata bed. The total thickness 

 of the Asaphus limestone is about 8 meters, and it is succeeded by the 

 limestone with Megalaspis gigas (12 meters) and the higher beds. These 

 higher beds are exposed in a more or less continuous section in the vicinity 

 of Mttsjo, something over a kilometer northeast of the railroad cut just 

 described. 



An interesting section occurs at Skattungbyn, near the northern end of 

 Siljan Lake, and about 40 kilometers northwest of Rattvick. 40 This we 

 did not visit, but it is significant in our discussion. The base of the sec- 

 tion is a layer of green limestone a foot in thickness and resting directly 

 on porphyry, of which it incloses angular fragments. This is followed by 

 green Phyllograptus shales with layers of limestone. The shales contain 

 Tetragraptus serra Brongn., T. quadribrachiatus Hall, T. curvatus Tqt., 

 Phyllograptus densus Tqt., Diclwgraptus octobrobrachialus Hall, Bidymo- 

 graptus minulus Tqt., D. gracilis Tqt., D. decens Tqt., and some brachio- 

 poda. From the inclosed limestone layers Holm has obtained Pliomera 

 tornquisti Holm, Megalaspides dalecarlica Holm, Niobe Iceviceps Dal in., 

 Ampyx pater Holm, AgnOstus tornquisti Holm. 41 



40 Tornquist : ofversigt ofver bergbyg-gnaden inom Siljasomrudet i Dalarne. S. G. U., 

 Ser. C, No. 57 ; Warburg., B. Guide, pp. 5-6. 



41 Holm : Ueber einige Trilobiten aus dem Phyllograptuschiefer Dalekarliens, Bin. K. V. 

 Akad. Handl., Stockholm, 1882, vol. 6, No. 9. 



