The occurrence of anthracite in this locality has been noticed and recorded by several observers, who seem to have overlooked some of its more remarkable peculiarities. At present, this mineral may be detected in a series of anastomosing vertical veins of calcareous spar, including, at the same time, angular portions of the claystone porphyry in which they are situate, on the upper north walk on the north side of the Observatory. The anthracite occurs, 1. In rounded, drop-like pieces, on which the calcareous spar has been moulded, not unlike the colophonite of Norway.