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Description: This rock is a gabbro – a coarse-grained, mafic igneous rock resulting from solidification of magma within the Earth’s crust (i.e., intrusive environment). Gabbro contains plagioclase (white mineral) and pyroxene (dark mineral) as the major mineral components, and may contain variable amounts of olivine and hornblende amphibole. This gabbro is from a structure called the ‘Shelbourne Dyke’ that represents a now solidified fracture that would have once channelled mafic magma to the surface from depth where it would have spread out as a lava flow. We see evidence of these once vast lava flows now preserved as the ‘North Mountain Basalt’ of northern Nova Scotia along the Bay of Fundy. The magmatic activity that resulted in the formation of this gabbro and the North Mountain Basalt is associated with the initial rifting of Pangaea and the formation of the Atlantic Ocean.