The Base of the Devonian

Abstract

My attention has recently been called to some very interesting comments on the problem of the delimitation of the Silurian and Devonian systems, which were made by Dr. Elles in her Presidential address to Section C of the British Association at Liverpool. I am so heartily in agreement with all the principles of the modern classification of strata, as laid down by Dr. Elles, that it seems of advantage to recall very briefly how closely these principles are adhered to in using the Ludlow Bone-bed as the local base of the Devonian in England.