In a preliminary note on the dolomite contaet-skarns of the Broadford area, Skye (Tilley, 1948, a), a brief account was given of the constitution and environment of these multizoned assemblages at the contact of the Durness limestone succession with the Tertiary Beinn an Dubhaich granite.1 No detailed survey of the numerous parageneses was then attempted, and it is the purpose of the present paper to fill this gap and to discuss the genetic problems of these skarn assemblages.

The confirmation of the presence of potassium salts in the Permian evaporites beneath the Whitby district, first found in the D'Arey Exploration Co.'s Eskdale no. 2 (Aislaby) boring (G. M. Lees and A. H. Taitt, 1945), and the discovery by Imperial Chemical Industries in their Eskdale no. 3 (Sleights), no. 4 (Sneaton), and no. 6 (Upgang) borings that these salts exist in workable quality and quantity, has been recorded in a recent historic paper by Dr. A. Fleck (1950). The successful outcome of this boring campaign may well lead to the outstanding development of the present century in economic mineralogy in Britain.

During the past twenty years considerable attention has been given to the compositions of the pyroxenes from basic igneous rocks. Hess (1941) reviewed the courses of crystallization of pyroxenes from mafic magmas and drew a trend line for the lime-rich clinopyroxenes. The present investigation was undertaken primarily to determine more closely the trend in the ferroaugite region, for here Hess's trend was based on the analyses of two pyroxenes from the Skaergaard intrusion and both of these are now known to be somewhat unusual types. The Skaergaard intrusion which is a strongly fractionated gabbroic complex is Particularly suitable for this study of the ferroaugites. Fifteen new analyses have been made for this investigation and twenty-three analyses of the pyroxenes from this intrusion are now available. Using nineteen of these, new trend lines have been drawn (fig. 1) for the Skaergaard clinopyroxenes.

The hypersthene-gabbro of Ardnamurchan Point is the earliest of the intrusions of Centre 2 of the Ardnamurchan complex as shown by 5. E. Richey (11, p. 208).I The mass is intruded into domed Jurassic sediments and Tertiary basalt flows (fig. 1). The main part of the intrusion is composed of rather fine-grained gabbro, containing 2-3 % of hypersthene which typically surrounds crystals of olivine. Marginally, however, the gabbro is a quartz-bearing variety, with a micrographic mesostasis. The outer contact is somewhat sinuous due to the fact that the intrusion has only been exposed to a comparatively small depth below its original roof. This same geological accident may account in part for the number of fine-grained, basic, granular masses that are locally abundant within the gabbro.

In this paper is described a series of three small pcgmatite dikes and the skarns produced by them in Dalradiau ealc-silicate hornfelses, and after full discussion certain conclusions are deduced as to the mode of origin of these rocks. This suite has not been described previously and lies to the south of Bunbeg quay and to the east of Loughlin island (fig. 1). Tim only published accounts of the area contain but passing reference to some of the features here described. In 1891 Nolan (1) merely noted the existence of 'remarkable beds of garnetiferous limestone withtremolite' near the small village of Bunbeg, whilst Zealley (2) in 1909 briefly referred to these hornfelses.