I am amazed, also.
A little while back, I ran across a magazine called "Christian History", and read an entire volume devoted to the life of Johnathon Edwards (Puritan minister, not V.P. candidate).
Apparently, Edwards was intensely interested in biology, and also wrote several interesting essays on the psychology of religious belief.
This comment about Cotton Mather seems to be along the same lines--both were men who pursued a broad range of studies, instead of devoting themselves purely to theology.
I've never thought of Puritans as learned or scientific men--but apparently, some were.