On a relatively rare recent beautiful spring day with no commitments beyond getting from Baltimore to Wilmington, Delaware by nightfall, I opted for heading up Route 1 at midday with time to briefly explore two accessible serpentine barrens along the way: Rock Springs and Chrome Barren Reserve,both in Pennsylvania. The trail through Rock Springs heads north from State Line Road west of Route 222.
In natural history circles, these barrens are touted less for minerals than the very rare plants that thrive in their unique environment. The soil, which is low in nitrogen, calcium, and phosphorous,but rich in magnesium and chromium, is nutritionally inhospitable to much vegetation otherwise indigenous to the area, but welcoming to other rarer plant species. Think serpentine aster, glade spurge, fameflower, lyre-leaved rock cress, prairie dropseed, and arrow-feather. Not seeing much growing that seemed unusual, perhaps April 14 was a bit early in the spring. There weren't many rocks to look at either.
The only interesting rocks I observed comprised roadfill for the Rock Springs parking lot shown in our title picture. They had it all over what rocks I'd spied in the barrens. They had been quarried from the ultramafic rocks beneath the earth at barrens similar to these. Among them was the antigorite in the picture at left, with portions sufficiently translucent and gemmy to refer to as williamsite.
The 340 acre Chrome Barrens Preserve, 59 of which the Nature Conservancy and Chester County Commissioners permanently protect, was my next destination. The main trail here detoured into brambles and dead ends and was difficult to follow. Much of the Chrome Barrens Preserve is deciduous forest. The most accessible rocks were in small alluvial deposits amidst occasional erosion along the trail. I felt justified in taking the chromite in serpentine pictured at left after reading how specifically the sign shown at right exludes rocks or minerals from what must not be damaged or removed
Such a beautiful day to be out in nature, but other locations would have appealed to me more. The day's schedule had been quickly conceived the night before. Realizing that this route to Wilmington passed through Chester County, I would have stayed up later the night before with The Mines and Minerals of Chester County, Pennsylvania by Ronald A. Sloto,2009. This 470 page labor of love has it all in terms of being thorough and specific. It will be my guide next opportunity to so linger when headed in a similar direction.