Got to mention that Pawtuckaway is a Ring Dike. It can be hard to see on the ground, but it's really obvious on a shaded relief map.
Good introduction to the geology here: http://fredlanga.blogspot.com/2008/08/meteor-crater-in-nh.html
"As an adolescent I aspired to lasting fame, I craved factual certainty, and I thirsted for a meaningful vision of human life - so I became a scientist. This is like becoming an archbishop so you can meet girls."