Monday, November 15, 2010


Council Rock in Montgomery County's Lorimer
Park, rising above Pennypack Creek
For 60% of my life, I lived on sedimentary landscapes.  I was raised in northeastern Ohio on the Glaciated Appalachian Plateau. I earned my undergraduate degree at Ohio University on the Unglaciated Appalachian Plateau, then sidled eastward to Pittsburgh, also on the Unglaciated Appalachian Plateau, to earn my graduate degree.  From there, I traveled south to Florida, taking up residence for seven years on sand-veneered limestone terrain that has repeatedly bobbed above and below the ocean over the eons.

Kali brought to my attention this morning, out of the blue, that I have now lived in one place for the longest span of time in my life:  22-1/2 years.  And, that time has been spent on the Piedmont.  I finally have some rock, some real rock, under my feet--not friable shale and slimy mudstone that weathers into clay, or sandstone that turns into grit, or limestone that can drop out from under you without warning.  Nope, solid metamorphic schist that's been here for nearly a billion years--some of the oldest rock on the planet.  And rock that produces some of the best garden loam on the planet.

Metamorphic rock does have one downside: it doesn't produce wonderful intimate waterfalls, the staircase cascades that defined my childhood.  Although the northern Piedmont is full of places with "fall" in their names, most are really just rapids. The only two real waterfalls that I know in the northern Piedmont--falls where water plunges straight down over a vertical cliff--are in Paterson, New Jersey (which has an incredibly impressive state- [if not national-] park-worthy waterfall in the very middle of its gritty post-industrial downtown) and in Ringing Rocks County Park in Bucks County, Pennsylvania.  And, even at Ringing Rocks, the falls has developed on an unusual and spatially-delimited metamorphic rock called diabase.  Rapids are common; real falls are rare. 
Council Rock, Lorimer Park
One of the most impressive outcrops of  metamorphic schist in my neighborhood occurs in a Montgomery County (Pennsylvania) county park called Lorimer Park.  There, rising dozens of feet straight up from the bank of  Pennypack Creek, sits Council Rock, so named because the local Leni Lenape Indians reputedly held important meetings near this geological landmark. Today, it's used as a backdrop for wedding photographs and as a place for kids to climb and explore.  
Eastern hemlocks clinging to Council Rock
It still retains a green mantle of Eastern hemlocks (Tsuga canadensis) despite the foot traffic and the white-tailed deer, which consider hemlocks dessert.  But, for me, it's a symbol of the first real firm foundation in my life.
November's late afternoon sun illuminating Council Rock


Grizz………… said...

Well, at least as a wandering Buckeye you didn't stay stuck in Florida's sand. Nope, you settled where there are real seasons, where snow and autumn leaves aren't abstract concepts. A state where, should you decide to pluck a stone from the earth at your feet and smite your unruly neighbor upon the head, you could commit such an act forthwith and not have to allot three days beforehand for actually finding an adequate smiting rock.

I say well done! And your photos are great.

Jain said...

I envy your knowledge of geology, I've always been a dope that way. I just assume that whatever I'm standing on will hold me. :o)

Lovely outcroppings, and I'm wild about Hemlocks. Waterfalls may be overrated.

Scott said...

When we lived in Florida, Grizz, we resided in Lakeland, just west of the geographic center of the peninsula and a bit closer to Tampa than Orlando. The only place where we could find natural outcrops of limestone were in the Hillsborough River at Hillsborough River State Park northeast of Tampa. We were definitely west- (Gulf-) coast oriented, but a few times we went over to the Atlantic, which included a visit to The Nature Conservancy's Blowing Rocks Preserve where waves have excavated limestone outcrops in the ocean. Otherwise, I would have had to subdue my unruly neighbors by throwing sand in their eyes.

Scott said...


I don't know where you're located exactly, but if you're very near Lake Erie, you're on the Lake Plain. If you're a bit further inland, you could be on the Glaciated Appalachian Plateau (which extends westward from the Pennsylvania state line to central Erie and Huron counties and eastern Richland County before it heads south). If you're a bit further west and south, you're on Till Plains, which have been glaciated. One of my "bibles" and most cherished books is called "Ohio's Natural Heritage," published in 1979. I doubt that it's still in print, but you could probably get a used copy on Amazon.

Though you're on sedimentary rock, you may actually be on firmer footing than I. Just a mile south of me lies the Huntingdon Valley Fault which has not been active in recorded history, but who knows...