XX.— Note on a Mississippian Spore Assemblage from Ayrshire, Scotland

Abstract

The material was collected by one of us (D.P.) from a series of grey siltstones rich in small, broken-up plant fragments, exposed on the foreshore south of Ayr, near Longhill Point. The siltstones outcrop in the short interval which here separates sandstones belonging to the lower part of the Millstone Grit from a succession of shales, siltstones and cementstones referable to the Cementstone Group of the Calciferous Sandstone Series (see Table on p. 288). The succession consists of a few feet of shales and cementstones passing downwards through sandstones rich in volcanic detritus into the bedded agglomerate, some 70 feet or so thick, of Greenan Castle, which is underlain in turn by several hundred feet of shales, cementstones, siltstones and sandstones. Spores were extracted by treating the material with cold concentrated HF for a week followed by Schulze’s solution for 24 hours. The residue was washed and treated with very dilute ammonia for a couple of hours. Permanent slides were made in canada balsam. A preliminary examination of the microspores has revealed the presence of the following genera and species (new generic or specific forms are not named). A detailed description of the spores will be published elsewhere by one of us (K.M.L.). Leiotriletes sphaerotriangulus (Loose) Pot. & Kr. L. gulafer Pot. & Kr. L. spp. Punctatisporites minutus Kos. P. obliquus Kos. P. cf. debilis Hacq. P. cf. nitidus H.S. & M. P. spp. Granulatisporites sp. Cyclogranisporites amplus McGregor. C. spp. Planisporites cf. kosankei Pot. & Kr. P. spp. Lophotriletes This 250-word extract was created in the absence of an abstract The authors are grateful to Professor J. Walton for providing research facilities at the Botany Department, Glasgow University and for his keen interest during the course of the work. One of us (K.M.L.) would like to thank the authorities of the Colombo Plan for the grant of a scholarship, and the Director, Birbal Sahni Institute of Palaeobotany, Lucknow, India for granting study leave.