and for this result the congealing magma must necessarily have been sealed in by strata through which its heat was disseminated slowly. For upon the most cursory inspection of the vein, the eye is arrested at once by the large masses of crystalline orthoclase, the heavy beds of a gray, brecciated quartz and the zones and columns of large leaved mica. It was to secure the latter that Mr. Wilson first exploited this locality, and only latterly have the more precious contents of the vein imparted to it a new and more significant character. The mica, called by Mr. Atwood, the superintendent of the work, "book mica," occurs in thick crystals, ranged heterogeneously together in stringers and "chimneys," and brilliantly reflecting the sunlight from their diversely commingled laminae. This mica yields stove sheets of about two to three by four or five inches, and is of an excellent, transparent quality. It seems to be a true muscovite, and is seldom marred by magnetic markings or crystalline inclusions that would interfere with its industrial use. Seams of decomposition occur, and a yellowish scaly product, composed of hydrated mica flakes, fills them. The mica does not everywhere present this coarsely crystalline appearance, but in flexures and lines of union with the quartz and orthoclase is degraded to a mica schist upon whose surfaces appear uranates of lime and copper (autunite and torbernite), and in which are inclosed garnet crystals of considerable size and beauty. The enormous masses of clean feldspar made partially "graphic" by quartz inclosures are a conspicuous feature of the mine. In one part of the mine, wooden props support an overhanging ledge almost entirely composed of feldspar, which underneath passes into the gray brecciated quartz, which again grades into a white, more compact quartz rock. It is in this gray brecciated quartz that the beryls are found. These beautiful stones vary extremely in quality and color. Many of the large crystals are opaque, extensively fractured, and irregular in grain, but are found to inclose, especially at their centers, cores of gem-making material.