You're right, John, starting at Lubec, Maine would make for a more accurate
"full cross country trip".  But if I did that I might feel compelled to have
my final destination as Bellingham, WA, or slightly north.   The
significance of the G. Washington Bridge, of course, is that where author
John McPhee begins his geologic cross country jaunt.  It's all about rocks.
In Maine our rocks are mostly granite.  And, as everybody knows, most folks
in Maine take their granite for granted.

Cheers,

Dave Gunning  &
Sammy,  Chief Rockhound