86 AUGITIC ROCKS. A variety of the same rock, in which the crystal line structure is scarcely perceptible, has received the name of ‘ anamesite ’ from Continental petrologists, after Yon Leonhard ; hut it cannot be regarded as im portant, the size of the crystals being probably only due to different rates of cooling. 1 Basalt. This rock is a dark, apparently homo geneous rock, in which the components are invisible to the eye, but under the microscope are found to consist of minerals similar to those of dolerite, namely, labradorite felspar, augite, and titano-ferrite. Amongst the most frequent accessories of the modern or Tertiary basalts, so as almost to appear an essential, is olivine. They also frequently contain carbonate of lime; and when amygdaloidal, the cells are sometimes filled with calcareous spar, or zeolites, probably formed by filtration after the consolidation of the rock itself. Werner found vesicles of water in compact basalt of Germany ; and Dr. Richardson, similar water-cells in that of Antrim. From the compact character of the rock, it was long supposed that basalt was a simple mineral sub stance, until Cordier, in 1815, examined under the microscope the pulverized grains, and recognised in them the constituents of dolerite. His observations 1 Zirkel’s recent work on the Microscopic Structure of Basaltic Rocks (Untersuchungen iiber die mikros. Zusammensetzung der Basaltgesteine).