I think that the possibility of the "Pawtuckaway Mountains" just west of Pawtuckaway Lake in Southeastern New Hampshire being the residue of an impact crater should be investigated. The rocky outcroppings form an almost perfect circle one mile across, with an off-center "lump" jutting up in the middle.
It ought to be easy to test, by examining the granite in the area for pressure fractures in the crystalline structure of the bedrock in the area.
It turns out that the "Mount Pawtuckaway Ring-Dike Complex" is actually the remnants of volcanic-type activity, occurring between roughly 120 and 130 million years ago.
"The available data suggest that the Mount Pawtuckaway complex represents a cross-section through a vertical conduit up which moved a series of magmas closely spaced in time." (Last paragraph of page three) Eby, G.E., 1984 (pdf file, acrobat reader required).
© Huw Powell