On the Ashprington Volcanic Series of South Devon

Abstract

There exists in South Devon an extensive series of igneous and quasi-igneous rocks occupying a considerable area, mainly east of the River Avon, which have as yet received scarcely more than passing notice, and the study of which is attended with much perplexity Sir Henry De la Beche noticed the Yalberton trappean rocks south-west of Paignton, which are included in our subject, and spoke of them as interposed between the Yalberton limestone and that of Watton, which forms the western termination of the Berry Head mass. The relations of the igneous rocks to the Devonian limestones will be considered de novo as we proceed. Dr. Holl mentions the rocks of this series in the neighbourhood of Totnes, Ashprington, &c, as “thick slates, in which much volcanic matter is disseminated.” He observes that“volcanic rocks are frequent,” and that “beds which are light-coloured often yield a red soil.” This was written with reference to rocks which occupy the ground between Harberton and the Dart. Though we might reasonably take exception to the term “slates” as not strictly applicable to any portion of these rocks with which we are acquainted, yet as it is quite certain that Dr. Holl well appreciated the importance of the group, and as no spot could be pointed out where they attain a greater development than [at] Ashprington and its neighbourhood, the provisional term “Ashprington volcanic series” has been here retained.