Today was great in terms of learning about what GPS and GIS can do as well as following up on some information.
First, the ballfields at the top of the sewershed are named after the quarries owned by the Lorrilard family and from which the snuff mill on the river’s banks was built!! ( http://en.wikipedia.org/wiki/Lorillard_Snuff_Mill) .
I was absolutely wrong about where the third avenue el depot was located. It was where the electric transformers are a block to the south