The Upper Ordovician Cephalopods of the Oslo Area

S ome years ago the late Professor j. KIÆR proposed to me to undertake a description of the Ordovician cephalopods of the Oslo area. When later I came to realize this plan, it soon became apparent that the Upper Ordovician presented a more rich and interesting material of cephalopods than any other division of the CambroSilurian, and the work was then restricted to this part. The material upon which this study is based is almost exclusively in the collections of the Paleontological Museum in Oslo. I have further has opportunity to examine material of Norwegian and related cephalopods in museums in London, Stockholm, Upsala, Tallinn and Tartu. Some specimens have also been borrowed for description. From Cambridge, Mass., U. S. A., I got photographs and a piaster east of the cephalopods from Herøya described by HYATT. To the keepers of all these museums I wish to express my heartiest thanks for the readiness with which they have given me access to their collections. During a visit in Halsingborg I was also received in a most friendly manner by Dr. G. T. TROEDSSON, who showed me his working material of cephalopods. As al ready mentioned, it is to Professor j. KIÆR that I owe the stimulus to these studies. He placed the collections of the Paleontological Museum at my disposal and rendered freely his encouragement and support for the work. The recollection of my highly esteemed teacher will always be one of deep gratitude. - Professor O. HOLTEDAHL has likewise supported my work and presented the paper for printing. Dr. A. HEINTZ, the present keeper of the Paleontological Museum, has always shown a friendly readiness to· assistance. Miss LILY MoNSEN has assisted at the photographing, Miss Liv BARSTAD and partly Miss LILL ToRBJØRNSEN have retouched the photographs and drawn the diagrammatic figures. Mr. M. SvEEN, the preparator of the Museum, prepared the slices, which made a finer study of siphuncles possible. My most respectful thanks are due to the University of Oslo and to the Fridtjof Nansens Fond for grants to the support of the work and to the Norsk Geologisk Forening for the printing of the paper.