Sentence:  Along Wappinger Creek in Dutchess County , past the white church at Fishkill , past Verplanck 's Point on the east bank of the Hudson , to the white <WSD>salt</WSD> crusted roads of the Long Island Rockaways there was a watching and an activity of preparing for something explosive to happen . 
Meaning of the word marked with <WSD> tags:  a compound formed by replacing hydrogen in an acid by a metal (or a radical that acts like a metal)