The first photo looks like a quarried face. I do know that bluestone was quarried in Woodstock, but I'm not sure how far away that town is from Catskill.
I did get my hands on a copy of "Quarries of bluestone and other sandstones in the upper Devonian of New York State" by Harold T Dickinson 1903 which list all the quarries in this area. A nice map included shows this area and list the spot as having quarries in operation, along with quarries no longer in operation. Another 1832 map has the words "Quarry Lands" opposed to the much smaller area a mile away that says "Stone Quarry". This coincides with Michael Kudish, author of " Catskill Forest: a History" in which he says most quarries were on less than an acre. The area I'm looking at is a meandering collection of stone heaps,and terraced surfaces that goes on for many acres.More soon
You should contact Glenn Kreisberg, who can be contacted through the NEARA.org site. Glenn lives in Woodstock, and wrote an article about the bluestone quarries and the large stone mounds (Indian) found there. He would be interested in your finds.