Oley Hill site dates to 2500 years ago

I asked Norman Muller about his dating result for the Oley Hills. They used OSL (Optically Stimulated Luminescence) to arrive at a date of 2500 BP, for one of the terraces at Oley Hills. He wrote:

Yes, the Oley site is much older than Cahokia.  I am of the opinion that the large platform stone mounds in the Northeast were inspired by the earthen mounds in the Midwest.  Or maybe the influence went in the other direction!  You are aware, of course, of that large geometric earthen mound in western MA (see LiDAR attachment; the mound is about 50 feet high and 200 feet long at the base; the top is precisely oriented to the cardinal directions.  I visited the site with Timreck and Lisa Gannon).