* I agree that the OP was talking about category 1. But as I'm discovering, there are a variety of other, older "collections" of "folk music" out there.
* Yes, the manuscript is referred to as the "Jones-Conklin" manuscript. There is a copy of the Jones-Conklin manuscript in the Indiana University library.
* New York city or state? In general, it depends on the context. The Jones-Conklin manuscript is from the far eastern end of Long Island [well east of New York city], which had a thriving whaling industry in the 1840's and 1850's. The Stevens-Douglas manuscript is from western New York state [the frontier in those days].