Published prior to 1923
View this photo at books.google.com
BH Photo #370963
This post doesn't help determine the type, date of construction, & of the subject bridge, but an attached screen shot of a portion of the 1966 Conklingville 7.5' topo map indicates the bridge may have existed into the 1960's.
The map states the area was aerial surveyed in 1965 and field checked in 1966. Excellent site!! Research of town or county historical records may be in my future.
I wondered this myself when I added the entry. I wasn't completely sure. Your points make complete sense and I agree. I will move the image over to the other page and leave this page up for the Stewart's Road Bridge if any information ever comes up.
While this postcard lists this bridge as the Stewarts Bridge Road bridge, it seems to actually depict the Old Corinth Road Lenticular Bridge just upriver http://bridgehunter.com/ny/saratoga/hadley/ . There are a few areas we can look at the confirm this:
1.) Design. The Hadley bridge replaced a 2 span covered bridge, and the abutments and pier were reused from this bridge. The arrangement of the pier (being offset towards the south bank so that it wasn't actually in the river during regular water levels), resulted in the mixed truss types, with a tiny approach span and a longer semi-deck lenticular truss. Given the unique conditions that allowed for this design to take place, it seems highly unlikely that an identical bridge could have been fabricated elsewhere.
2.) Size. There are a few clues indicating that this is the Old Corinth Road Bridge as opposed to the Stewarts Bridge. Satellite view indicates that there is a remaining pier for the lost Stewarts Bridge Road bridge, however the pier is roughly in the center of the river, with (at best guess) about 100 feet on either side towards the abutments. Thus the bridge depicted couldn't really work here, as if we follow the Old Corinth Road Bridge measurements (which has the same number of panels as the one depicted in the postcard and turned in with a 136ft main span with 40ft approach) we see that it doesn't quite fit.
3.) Visual distinctions. Aside from the identical truss type, I also immediately made a connection looking at the postcard that I recalled from my site visit. On the other side of the river the roadway makes a 90 degree turn and is abutted by a rock face. Looking at the roadway alignment of Stewards Bridge Road, it doesn't seem like the roadway would have to have made such a dramatic turn. Also looking at the bridge upstream we notice the same rock face along the road.