Natural Mid-Atlantic : PA Silver Mine Park

Monday, September 27, 2021

PA Silver Mine Park - Clams and an Oyster

Silver Mine County Park in Lancaster County is a local gem of a walk that combines beautifully a maintained paved path and interconnecting hiking trails along Pequea Creek, a tributary of the Susquehanna River. I was able to fit in a fast five miles using all the trails in combination before meeting a fellow environmental historian at the Conestoga Area Historical Society Museum for Fall Fest. Climbing a synclinal bluff, I did some hawk-watching - fall migration is in full swing - and counted 16 hawks of four species, vultures, and an eagle. The fall weather is most definitely here and there is a hint of yellow in the leaves.

Pequea Creek flowing to the Susquehanna

Paved trail is great for kids biking and people needing mobility assist.

Despite its small size at only 151 acres, the paths and trails are laid out in such a way that you really see all aspects of what made this area attractive to early mining industry. Ore mining and lime kiln operations spanned from the Revolutionary War Era to the Civil War. There are both small open pit and "gopher hole" shafts to find along the Geology Trail and two limestone kilns to see right on the main trail. The main shaft entrance is for safety's sake is closed up with a little slit left open for bats. Anticlinal folds and dips in the local geology are close to the surface and made this an attractive prospect for silver, though not much was found. Instead, the operations turned to lead and limestone production before closing at the end of the Civil War.

Main entrance - now walled off.

What impressed me about climbing around this well-worked slope was the number of hand dug gopher holes that were excavated by hand - no machinery - to reach the main shaft below. Gopher holes served a few purposes such as providing fresh air to the miners below and as escape routes in case of a ceiling collapse. I've noticed while hiking and exploring 18th and 19th century mining areas how common it is to find these hand-dug holes and how careful you have to be not to accidently tumble into one that has been covered by hundreds of years of accumulated forest debris! The Wind Caves area, once mined for magnetite on the down slope towards the Susquehanna is peppered with gopher holes. It's wise to know the history of the area when exploring off trail in these parts!

A gopher hole shaft dug to access the main shaft.

Gopher hole shaft nearly covered by forest debris.

Gopher hole in the curve of the syncline.

Once the leaves drop it will be easier to see evidence of blasting activity. A dangerous job for a man with a steel drill and another with a sledge hammer and a load of powder, blasting was the most expedient way to access the ore-rich rock on a bluff or shoulder. Waste rock cascades down almost every slope towards the paved path where there are woods. Beyond the mowed fields and pavilion sites, the creek banks, freshly scoured by last week's heavy rain, are cluttered with waste rock. I glimpsed the tell-tale half-cylinder bore hole of a blasted boulder lying in shattered rock on the bank.

Lime kiln

In addition to agricultural lime, the twin kilns produced quick-lime which was especially useful when maintaining household privies to both kill the smell and disinfect the contents. Ew. But as I was later to learn from the friend I was meeting at the Fall Festival, old privies make for some really great archeology and all that quick lime over the centuries have made some pits quite sterile. Still - ew. Later I walked a section of road to make a loop back to my truck and passed several large roadside quarry cuts that supplied the dolomite and limestone for that important phase of the operation.

Quarry lake

Black Shale of the Conestoga Formation

Fossil mud cracks in dolomite-limestone.

Conestoga Phyllite (metamorphosed shale) with a blasting bore hole.

I explored the small stream that emptied from the two quarry lakes above the paved trail and found it covered with Asian Clams which is a concern because they quickly replace native mollusks. I looked hard for any native species and could find none. The bottom of the little stream was filled with them and their wormy looking excretions which cause algae blooms and browning of the stream floor. These clams are everywhere in the Lower Susquehanna basin and cause problems for man and fishy beasts alike.

Tiny Asian Clams,

I was happy at the end of my hike to find Blue Lobelia where I'd parked my truck but had walked right by earlier on! I forced myself to stop for a few minutes and enjoy this most beautiful of blue fall wildflowers as it contrasted with a nearby bank full of goldenrod. Slow down! What's the hurry?

Great Blue Lobelia, Lobelia siphilitica

Canada Goldenrod, Solidago canadensis

Just up the road and just a few miles away, the Conestoga Area Historical Society was open for the morning and the Fall Fest was underway. I met Dr. Lasi and her wonderful Plott Coonhound, Oyster by the iconic Conestoga wagon out front. Clams and an Oyster!