Above and upon #igneous #dikes
The feature sure looked like a #dike on #satellite view, and a ground check confirmed it. Probably a late #Triassic or early #Jurassic intrusion into #Proterozoic Dedham #Granite, as #Pangea rifted. At Black Rock #Beach, #Hingham, #Massachusetts, #NewEngland #geology USA.
Satellite view from #AppleMaps, #photo by me.