This photo was from the Mercer's web site and shows the building under construction in 1915.
Ringing Rocks Park in northern Bucks County. The centerpiece of this park is a 5 acre field of boulders in the middle of the woods where one out of three boulders ring like a bell when struck with a hammer or another rock. The whole place is very mysterious and several web sources say that no plant will grow in the boulder field (though I did see a dead sapling), birds will not fly over it and animals will not cross it. The average depth of the boulder field is about 14' which makes the fact that nothing grows there not so mysterious and without plants you would not expect to see any animals. I do wonder though what forces brought these boulders here and concentrated them. As to the ringing, no one is exactly sure, but most believe it has to do with their composition and geological stress. Whatever, it was cheap fun.
Addendum: I thank my firiend Chris who found the following explanation of Ringing Rocks.
"The boulders are made of a substance called diabase which is basically volcanic basalt. This is one of the largest diabase boulder fields in the Eastern United States. The boulders have a high content of iron and aluminum and were thought to have broken apart during the Pleistocene Epoch probably about 12,000 years ago. The boulders were created through many years of freeze-thaw cycles that broke up the diabase into individual pieces, a process known as "frost wedging". The rocks may then have accumulated in this one area as the water saturated soil provided lubrication for the stones to "creep" downhill to their present location, a process known as "solifluction". This could have happened during the prior ace ages when overlying most soil literally slid over the frozen permafrost below, carrying the boulders with it."