Tuesday, December 30, 2008

Rock Shelter(s) by the Wissahickon

There are a few, really amazing rock shelters and shelter-like formations along the Wissahickon.
The upthrust of a long ago weathered-away mountain chain has left us with some inspiring crags, folds and overhangs made of the local gutrock.

As far as I know, there has been no serious archaeology done here, in spite of the fact that local lingo has given these shelters names like "Indian Cave", "Council Rock" and such like...

and another...

Sunday, December 28, 2008

Rock wall seen from bottom of "bowl"

Here's a section of the wall from yesterday's post.
You can see it tracing the edge of the ridge defining the northern boundary of the bowl.

A close up shot of a portion of the rock wall, here consisting of long, flat boulders, stacked end-to-end. Note the gap between the shelf on the middle boulder and its neighbor.

What is this?

Not far from the complex described yesterday, in fact, just a "stone's throw" away (and you will indulge the author in his puns, thank you) is an interesting boulder.

This isn't a stacked boulder, the crack that acts as the separatrix here does not persist to the other side of the boulder. Still, the boulder does look "worked" somehow. Speculation?

Saturday, December 27, 2008

Don't call it a comeback...

Sorry I've been gone so long. I've been tending to my academic career. As that seems, more or less, neatly in hand right now, I've taken to scouting some new locations.

Anyhow, I found the following structure at the end of a long stone wall, terminating on the shoreline of the Wissahickon Creek. The whitish rock at the bottom is a mostly quartz rock. note the several wedged and propped rocks.

The boulder on top abutted several other long, flat boulders that began a steep climb up the valley wall:

Following the boulder line up the hill, it eventually coalesced into a long, winding rock wall.

For most of its length, the wall skirted the edge of a huge, half-bowl shaped depression in the valley wall. The bottom of the bowl possessed a shallow grade, and was very nearly flat over large distances, in contrast to the near-cliffs that trace the contours of the Wissahickon for most of its length.
Descending into the bowl, seen over the edge of the wall, the terrain was mostly unremarkable. However, near the midpoint of the bowl, I noticed the following confluence of boulders.

The two large boulders frame a set of smaller boulders in the distance. Taking my compass out, I noted that the summer solstice sun would rise directly over the midline of this collection. Viewing the paired boulders from the boulders seen in the distance (straddling this midline), we see

and (flattening the camera's angle of attack)...
Note there are *2* boulders in the foreground. The one closest has a notch in it, or more accurately, a sharp point near its apex. Standing between the two boulders in the background (as mentioned above) you would see the summer solstice sunrise directly over this pointed boulder. Conversely, standing here, one should see the winter solstice sunset between the vertical extension of these twinned boulders. Too bad I just missed this sight by a few days...Anyway, here is another view of the same rock. Note its almost "manitou stone" -ish profile.

The other side of this bowl/vale was framed by a gurgling stream with some truly striking, but certainly natural, rock formations.