In the course of my work on Jade Axes from sites in the British Isles (PPS, XXIX, p. 133) I had occasion to consult descriptions of jade axes from Europe and to make notes on all those in publications available to me. I have now plotted on an outline map of Europe (fig. 1) the sites of recorded jade axes and have added also the locations of the few jade axes from France in the British Museum, Ashmolean Museum, and in the Wellcome Historical Medical Museum, which I have examined.This map is far less complete than that showing the distribution of jade axes in the British Isles, op. cit., fig. 4, which shows the location of every jade axe known in museums or in private hands as well as a few mentioned in the literature but not traced.The new records of British axes, recorded at the end of this paper, have been shown on the outline of the British Isles, included on the present map which reveals a large increase in the concentration in East Anglia.As regards Europe, apart from the few jade axes from France mentioned above, the records plotted are confined to those known to me from publications and I have had to rely on the authors' identifications of the materials used. These are confirmed by density determinations for a great many of the axes from Germany and for a few of those from Italy.

Several years ago during the investigation of neolithic chambered tombs in Galloway a fragment of green jade polished on two opposite flat faces was found in the floor of the ante-chamber to Tomb I at Cairnholy in Kirkcudbrightshire. It was only about 3 centimetres square and 1.5 centimetres thick but, nevertheless, Professor Stuart Piggott and Mr T. G. E. Powell recognized that it had once formed part of a flat triangular axe of a type already known from several places in Scotland. A fine collection of such axes in jade existed in the National Museum of Antiquities of Scotland in Edinburgh. In an appendix to their paper on the chambered tombs Piggott and Powell listed the jade axes recorded from British and Irish sites and republished the map compiled by Miss L. F. Chitty and published by Sir Cyril Fox in 1933. This appendix also contained brief notes supplied by me on thin microscope sections of the Cairnholy fragment and of five other British axes reported to be made in jade. Some of these identifications were only partly correct, and have now been revised (see below, pp. 145, 158, 159 and footnote 2, p. 153).Some years later the question of the identification of the material of reputed British jade axes arose again and it was decided to examine as many of the axes in Piggott and Powell's list as could be borrowed and to utilize in their examination determinations of density and refractive index, and, where possible, to obtain X-ray powder photographs and to have thin sections prepared.

I. I ntroduction I n the northern coastal region of Brittany, in the neighbourhood of Trégastel and Ploumanac'h (PL XVIII), to the north of Lannion, a red, mainly porphyritic, granite is admirably exposed in shore and inland sections, and is remarkable for the number of xenoliths which it contains, of a kind usually referred to as basic segregations or basic patches. Especially clear evidence is available to prove that these inclusions have had their origin in hybrid rocks formed from an earlier intrusion of olivine-norite. In view of the similarity of the xenoliths to basic patches that occur in other granites where evidence of their manner of formation is not so clear, it has been thought desirable to place our observations upon record. The red granite of Trégastel and Ploumanac'h forms the outer and oldest member of a complex that consists of several distinct intrusions of granite and occupies the country between Ploumanac'h and Trébeurden, an area of some 40 square miles. It was regarded by Prof. C. Barrois (1903) as being of Devonian age since it has escaped the movements and foliation which have affected the older rocks with which it is in contact, but the more recent explanation of the Geological Survey map places its intrusion at the beginning of the Carboniferous. The Geological Survey map shows this granite-complex asconsisting of three granitic masses. A centrally situated ‘granulite ’ in the He Grande and neighbouring mainland; an outer ‘granite porphyroïde rose ’ at Ploumanac'h; and, between these two,

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