A few more shots from the walk along the Atlantic Path in Rockport.
What a day to sit and gaze out at distant shores.
In the words of Paul Morrison (GoodMorningGloucester's fact checker extraodinaire), gabbro is a type of igneous rock which filled that crack in the granite from below and made a dike. This occurred in the Ordovician period about 450 million years ago when all this rock was also miles underground.
You can more about these volcanic rocks on this Oregon State University site.