Some Aspects of the Siluro-Devonian Boundary Problem

Abstract

The writer made a journey recently on the Continent to study the various facies of the Lower Devonian in connection with work on a fauna from New Zealand. Although not directly concerned with the lower limit of the Devonian System he gathered certain information regarding faunas near that boundary. This was especially a consequence of an invitation to the international excursion in May, 1937, arranged by the Prussian Geological Survey to discuss the Siluro-Devonian boundary and view a series of trenches at Hüinghausen, Westphalia, which, it was hoped, would expose the passage beds between these systems. The Prussian Geological Survey generously allowed the writer to collect somewhat later from these trenches. Professor Pruvost also invited the writer to examine the collections from Liévin at Lille, and later loaned a series of specimens for more detailed examination. For all these kindnesses the writer expresses his thanks. Mr. S. H. Straw has kindly read through the manuscript and made many valuable suggestions, and the writer had the benefit of discussion with Professor Richter of Frankfurt who also helped with material for comparison. To the authorities of the British Museum, the Museum of the Geological Survey, and the Sedgwick Museum the writer is indebted for the loan of, or access to, figured specimens. He also acknowledges a grant from the Royal Society which enabled him to make a journey on the Continent.