Thanks to our beloved member, "turtle", I have found that the lock was built 220 years ago this month. The construction of the lock, then, would have taken place under Henry Drinker. This information was gotten from the Wharton Ledgers.
Or rather the 1700's (namely 1765), if John Pearce is correct. See Heart of the Pines, pg. 30. Unfortunately, Pearce does not cite a source for this information.
Jerseyman,
What was the nature of the "herring fishery" that was located at Mordecai Landing?
As for the location of the dam on Sleepy Creek, I know for sure that there was a dam at the location I linked to previously, but perhaps there was an earlier dam at the mouth of the creek. I will...
Thanks to Jerseyman's research, I found the following additional information concerning David Fisher and Mordecai Landing:
From: http://archive.org/details/documentsrelatin35newj
BTW, Don...are you thinking of the fish factory in Great Bay? If there was a herring hatchery at Mordecai Landing, then it would have probably been on Meekendam Creek, here:
http://maps.njpinebarrens.com/#lat=39.62744095467052&lng=-74.62421536445618&z=17&type=nj1930&gpx=
Don, well the mill site on Sleepy Creek was just at the boundary of Washington Township. I have little doubt this is the mill being referenced. BTW, welcome to the site. Looks like you have a keen interest in local history.
You are on the right track, Don. The location of the sawmill on Sleep Creek was about here:
http://maps.njpinebarrens.com/#lat=39.691799668143815&lng=-74.68141078948975&z=17&type=nj1930&gpx=