1. I ntroduction . In the Quarterly Journal of the Geological Society for 1901 (vol. lvii, pp. 267–84 & pis. x-xi) is a paper by one of us, in collaboration with Prof. C. Lloyd Morgan, dealing with the igneous rocks and the associated sedimentary deposits of the Tortworth Inlier. The present communication may be regarded as, to some extent, supplementary to the above. Full references to the earlier work on the district having been given in the paper just mentioned, they will not be repeated here. The field-work has been carried out by one of us (S. H. R.); the identification of the fossils, involving the re-examination of the various public and private collections, by the other (F. R. C. R.). The expense of the work, which has involved the digging of a number of trenches and the opening-up of a series of old quarries, has been lightened latterly by means of a grant from the British Association for the Advancement of Science. We are much indebted to the landlords, the Earl of Ducie, Earl Fitzhardinge, and Sir George Jenkinson, Bart., for their kindness in facilitating these excavations. We desire also to thank Mr. J. Harle, Lord Ducie's agent, and Mr. J. Peter, Lord Fitzhardinge's agent, for help and information. The Llandovery rocks crop out along an area generally from 1 to 2 miles wide, which follows the general trend of the Carboniferous Limestone rim of the Bristol Coalfield, and stretches in a north-westerly direction from Charneld Green to the neighbourhood of