Echinoidea from Western Persia

J. W. Gregory, Ethel Currie
1920 Geological Magazine  
apart from volatile agents-is limited to silica. Where the diopside masses have been engulfed as inclusions in the igneous gneiss, the rock is traversed by felspathic veins derived from the fluid magma. The writer wishes to record his indebtedness to Dr. Harker, F.R.S., for encouragement and critical discussion during the progress of these studies. EXPLANATION OF PLATES IX AND XI. PLATE IX. FIG. 1.-Forsterite Marble, Sleaford Bay. The minerals shown are calcite (turbid), dolomite (limpid). The
more » ... mite (limpid). The dark grains are forsterite, showing 010 cleavages. Near the centre is a basal section of edeniie. Magn. 28 diameters. Fie. 2 -Forsterite Marble, Sleaford Bay. Constituents: forsterite, with serpentinous decomposition, calcite, dolomite. Twinning lamellae in dolomite are seen in relation to the rhombohedral cleavages, in the clear grain below on the left. Magn. 28 diameters. PLATE XI. FIG. 1-Diopside Rock, Sleaford Bay. The dark bands are diopside. and the white are quartz % T eins. The reticulation of the latter is clearly marked. FIG. 2.-Diopside-Microcline Rock. The clear central area is microcline. In the upper half of the section are basal sections of scapolite showing 110 cleavages at right angles, and diopside. Magn. 28 diameters.
doi:10.1017/s0016756800106934 fatcat:gggtmrsf7raulmicz4xbfvbk6e