Tinguaites from EIfdalen and Ruphachthal: Basalts from Madagascar and the Soudan
In connection with the investigation of ægirine-anorthoclase rocks from Abyssinia, belonging to the grorudite-tingusite series, an examination was made of specimens of the so-called green phonolite from Elfdalen, which in the British Museum collection accompanied the more ordinary brown and red porphyry from that locality. In the descriptions of the well-known porphyry quarries of Elfdalen, mention is made of this green variety as occurring only in boulders. Törnebohm was the first to record the occurrence of these rocks in situ, and to describe their characters, They were found in the form of dykes in the neighbourhood of Heden, near Särna, Dalarne, Sweden, and were interesting as containing cancrinite in clear, well-defined porphyritic crystals as undoubtedly a primary constituent.