New Laurentian Fossil

Abstract

MR. JAMES THOMSON, of Glasgow, who has been for some years on the out-look for fossils in the Laurentian rocks of Scotland, and has searched parts of Argyleshire, Inverness-shire, Ross-shire, and Caithness with this object, has lately been rewarded by the discovery, in the neighbourhood of Tarbert, Harris, of what is regarded by every Palæontologist who has seen the specimen as an unquestionable organism. It forms part oi a limestone bed intercalated with dark grey shale, and occurs in the midst of highly metamorphic rocks (among them a graphite granite), which were regarded by Sir Roderick Murchison as of Laurentian age, and which have ever since passed as such—no doubt being entertained as to their antiquity by Dr. Heddle, of St. Andrew's, who has geologised over the whole of Harris.