Excerpt from Austin Brook Iron-Bearing District, New Brunswick
In the southern and western part of the area eruptive rocks of basic character are found intruding into the porphyry. These rocks may b'e classed as gabbro or diabase. They are usually of a greenish grey colour, with a granular to fine tex ture. Other intrusions in the porphyry are numerous quartz veins. These are also very common in the ore. But are rarely seen in the gabbro. They vary in size from a fraction of an inch up to several inches in Width.
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