Question

In what period did NYS salt layers develop?

Answer 1

Esuit missionaries visiting the region in 1654 were the first to report salty brine springs around the southern end of "Salt Lake," known today as Onondaga Lake.

Hope this helps!
(This is from Wikipedia)

Answer 2

The correct answer to this open question is the following.

In the prehistory of the state of New York, salt layers developed in the Silurian period, approximately 400 million years ago. In that time the sea level lowered, exposing some parts on the western side of the territory. This increased the concentration of salt in the land. The Silurian period lasted 24 million years.