Coordinates were updated from the original on 3/21/04. You are looking for a .30 caliber ammo box.
A system of dams and locks allowed Schuylkill Canal traffic to travel on several sections of the Schuylkill River. Muhlenberg Township has created this little park around what is left of Kelly's Lock. Felix Dam used to be just upstream of here; there is also another cache there.
The Historical Society of Berks County gave me some good insight into the Schuylkill Canal, stretching from Philadelphia to Port Carbon: a distance of 108 miles. The Schuylkill Navigation Company operated it from 1825 to 1917. Most of that boat traffic carried anthracite from the coal regions up north to Philadelphia. There were 92 locks on the canal to overcome a 588-foot difference in elevation. There were numerous locks (all 80 feet long and 17 feet wide) and dams in Berks County, most of which were destroyed during the Schuylkill River reclamation in the 40's and 50's.
There are lots of items to note at this tiny park: Some historical info is posted at the site. Nearby is a marker (N40° 22.440 W076° 57.296) from the War Department, embedded in stone. Across the street is a root cellar. And yes, the airport is nearby. You may hear planes flying low overhead but don't worry: you are not that tall. Most importantly: the underbrush will get thicker as the season gets warmer - be warned.