You are absolutely correct , of course, about a ridge not being ideal location for an AM station transmitter; it is best located near water for conductivity. This was back before so much information was readily available on the internet, and honestly if I knew then, I don't remember why this site was chosen , and not another. Therefore, i don't know why they attempted to put the towers where they did. All I remember is the group opposing the application complained it was in the "viewshed" of the Roosevelt Estate. How far that complaint went on its own is also unknown. As I said first adjacent 1190 WLIB , NYC also objected.Was that ridge location the only land available? Generally, the last place you want an AM transmitter is on a ridge, hill, mountain or any other kind of "highland" location.
Swamps, marshlands, tidal plains and platforms in the ocean are the best locations.
* My only source of information back then was the then respected and reliable Poughkeepsie Journal.