INTRODUCTORY PART. 

 Historical. 



As i; 



is the case with by far the majorit\- of the Ordovicic-Siluric 

 fossils of the Kristiania region, the Strophomenids have not yet been at 

 all systematically studied. The fossils have been determined and named 

 for stratigraphical purposes, but the paleontological work in most cases 

 still remains to be done. 



The various geologists who have worked at the stratigraphy of the 

 Kristiania region, — studies that were commenced by Sir Robert Murchison 

 in 1844, and continued by the Norwegian investigators, Th. Kjerulf, 

 T. Dahll, W. C. Brøgger, J. Kiær, and the present author, — have thus 

 given lists of fossils from various horizons and various minor districts of 

 the region, and these lists also afford us an impression of what has been 

 found and identified in the group of fossils that is described in the present 

 paper. 



In various papers dealing with the stratigraphical succession of the 

 »Territor}- of Christiania«, Mltrchison ^ mentions different fossils from the 

 series, but no Strophomenids, the Lcptacna lata cited by him from the high 

 Silurian being now known as a Chonetes. 



The first real list of fossils from the Kristiania region was given by 

 Th. Kjerulf in a paper »Lieber die Geologie des südlichen Norwegens« ^. 

 (In a previous paper »Das Christiania Silurbecken« ^, under the general 

 remarks on the Cambro-Siluric System of the region he also mentions a 

 few Strophomenidae ^Lcptaena de pressa, rugosa, eug/yp/ia<^.) 



1 ,On the Palaeozoic Deposits of Scandinavia', Ouarterl3- Journal Geo!. Soc. I, p. 467, 

 1845. Forhandlinger ved de Skandinaviske Naturforskeres 4de Mode i Christiania, 

 1844, p 287. 1847. 

 and others. 



- Kristiania 1857. 



3 University S3-llabus 1855. 



Vid.-Selsk. Skrifter. I. M.-N. Kl. loi,. No. 12. 1 



