re: Images:
I was thinking that our Adirondack would probably be Pumice.
I found this photo while doing searches and was taken aback:
From: http://www.casdn.neu.edu/~geology/department/staff/colgan/iceland/veidivotn/dv015.htm
These 'blocks and bombs' have also have a familiar Martian look to them:
From: http://www.geology.sdsu.edu/how_volcanoes_work/Tephra.html
It's that darn volcano to the North of Gusev. Makes me wonder if there was water in Gusev, how much was left and how often did that volcano to the North errupted...
