Preface. 



The present contribution to Arctic PalfBontoiogy is the result of 

 studies made principally during a stay at Yale (Peabody) Museum, New 

 Haven, Conn., U. S. A. Besides having at hand there one of the largest 

 scientific libraries in America, I was also greatly assisted by the exi- 

 stence in this museum of precisely the material that I needed, viz, fossils 

 from coi-responding horisons in typical localities on the American Conti- 

 nent. Of even greater importance to me however, was the fact that 1 

 had oppoitunities of daily inteiTourse with the learned palaeontologist 

 Professor Charles Schuchert, Curator of the palaeontological collections 

 at Yale University, one of the greatest living authorities on American 

 Ordovician, Silurian, and Devonian faunas and their Arctic development. 



Furthermore Schuchert gave me an opportunity of studying in the 

 field under his guidance, the eastern N. American Silurian and Devonian, 

 in most beautiful sections in Maryland, Virginia and W. Virginia, on a 

 delightful 8 days' excursion during the spring of 1913. 



It is not only a duty, but a great pleasure for me to take this 

 opportunity of expressing my heartiest thanks to Professor Schuchert 

 for all that he did for me during my stay in America. 



Christiania November, 1913. 



Olaf Holtedahl. 



