_Amphibole-schist_, often styled _epidiorite_, consists of foliated hornblende, or its greener ally actinolite, associated with granular felspar and sometimes with equally granular quartz. The amphibole being usually prismatic, the crystals are found with their longer axes arranged in parallel planes, and often streaked out parallel to one another. Minute wrinklings, due to subsequent yielding, are not so frequent as in mica-schists. Amphibole-schists occur commonly as knots and somewhat irregular masses among mica-schists, and represent basic igneous rocks that were interbedded or intrusive in the sedimentary series. The pyroxene of the original rock has become recrystallised as hornblende, and the felspathic constituent has rearranged itself in granular forms. J. J. H. Teall[95] has described in interesting detail an example from the older rocks of Sutherland, and his paper contains a useful discussion of problems of pressure-metamorphism. AMPHIBOLITES Hornblende-schists are often seen to pass into true diorites; but they also have relationships with the more puzzling rocks known as _amphibolites_. These, again, graduate into _pyroxenites_, or rocks rich in pyroxene, with granular quartz and triclinic felspar, and into _eclogites_, which may be defined as pyroxenites with garnet. Pyroxene-eclogite, in South Africa, is associated with diamond[96], and fragments of exploded eclogite abound in the igneous vents from which the diamonds are extracted. What has been called "pyroxene-granulite" is a dark granular eclogite, including rhombic pyroxene side by side with garnet, and associated, in Saxony and Skye, with igneous intrusions. In both localities it has been shown to result from the inclusion of basic rocks, such as dolerites and gabbros, in a bath of some invading magma. The lens-like form of the Saxon masses, and the occurrence also of sheets of pyroxene-granulite interlaminated with fine-grained granite, were till lately attributed to the rolling-out action of pressure-metamorphism. By what H. Credner calls a complete reversal of opinion, due mainly to the opening of new railway-sections, the granular eclogites of Saxony are now regarded as products of extreme contact-alteration, combined with igneous flow[97]. A. Harker[98] similarly points out that examples in Skye are derived from basaltic lavas, into which gabbro has intruded, producing a complete reconstruction of the rock.