294 ON THE IGNEOUS METAMORPHOSIS [Ch. XIV. CHAPTER XIV. ARE THE PRIMARY SCHISTOSE ROCKS SEDIMENTARY DEPOSITS ALTERED BY THE CONTACT OF IGNEOUS ROCKS? Passage of primary slates into secondary rocks. — Transitions of two kinds — mineral and mechanical. — The latter no criterion of identity. — The relative position of strata not easily determined. — The lias group of the JBotzberg. — The capability of caloric to alter rocks. — Lyell’s remarks on this subject. — Sir James HalPs experiments on the fusion of rocks. — The state of rocks next actual lavas —also next trap —in Skye — in Anglesea —in Ireland. — Dolomization. — Strata next igneous rocks only partially altered. — These changes similar to the effects of caloric — condition of primary strata next granite — indicates a transmutation of one earth into another. — The contact of ignited granite and sedimentary deposits disputed. — The arrangement of primary slates incompatible with their being altered deposits. — These slates contain elements not found in sedimentary rocks. — The transfusion of alkalis analogous to that of magnesia in dolomite. — Objections to such transfusions.—The primary slates of Dartmoor—and the Hartz — said to be altered greywack^. — Those of the Alps altered oolitic strata. — The association of gneiss and limestone in Jungfrau —of granite and limestone in Glen Tilt and the Pyrenees. — Conclusion. The metamorphosis of stratified deposits by the contact of igneous rocks in a state of fusion or incandescence, appears to be established by such a legitimate train of deductions, that it will probably be esteemed an act of great presumption to dispute its accuracy. And any objections advanced against this hypothesis, may naturally meet with a less candid consid eration than the topics already discussed; because it is the offspring of the Plutonic theory, which has grown with its growth, and which certainly is so plausible, and so well adapted to give strength and support to its parent, and is withal so fascinating, that even its adversaries must attack it with no little reluctance. In a former chapter it was attempted to prove, that the evidence bv which the analogy between the primary and