Making New England rocks

[OldEastRR]

All the rock casting molds I've seen are of rough, jagged sharp-edged rock face like you find in the Rockies or the West Coast, none of which look right for an Eastern US scene. Smooth, rounded surfaces or at least muted edges of broken rock seem to be the norm there,  especially around rivers. So I'm trying to remake Western-style rock castings into Eastern ones. Here's a first attempt, made by sandpapering and grinding down the sharp edges (left side) that it started with (right side). I plan on filling all the seams and small cavities around the rounded rocks with plaster or sculptamold to make all smooth rock. How does this look to you Eastern guys?
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[Ed Kapuscinski]

It's tough to tell without a comparison photo with what you're going for.

[dougnelson]

Although the eastern mountains may be older, more worn and rounded, eastern rock cuts are more likely to be more sharp-edged than rounded.  Eastern rock cuts may also have more vegetation in and around them than western rock cuts where more of the geology is exposed.  I think your vegetation treatment may be more important than the rock castings.  Post some photos of the area you are modeling.

Reaching back to my college geology, exposed boulders in glacial till may be somewhat rounded, but otherwise bedrock cuts would show sharp edges with exfoliating layers of rock.

[Scottl]

I think we need to see an example of what you have in mind.   That looks vaguely like some of the less resistant shale and coal formations I associate with parts of the mid-western Appalachia.  People sometimes use ceiling tiles to simulate that but it is hard to make convincing.

I recall the field trips from my days at UMass and the rock there was pretty solid and angular in cuts all through the region.  But as Doug points out, natural exposures might be more rounded by long term weathering, and boulders in till or other similar sediment deposits tend to be rounded, but distinct objects rather than part of a smooth feature.  Exposed sediment will form slopes naturally (or is graded in cuts) that form fairly consistent slopes that extend out from the base.  I don't recall exposed sediment cuts remaining unvegetated for long.

There were river beds of hard rock that were smoothed nicely by water.  The river near Shelburne Falls MA below the dam is one example I recall https://www.youtube.com/watch?v=4AABtuyyMos.  It looks cool, but is not something you see very often in nature.

[peteski]

New Hampshire (the Granite State) has lots of exposed . . . granite. I don't recall the rock faces having rounded features - granite is a fairly hard rock. I would also like to see some photographic evidence of New England rocks having rounded features.

[Scottl]

Granite can be rather massive (minimal structure), so when it is naturally exposed it is often quite smooth and rounded.  In rock cuts, it is usually angular and faceted like most rocks.   If it makes a rock face, it is usually hard enough to hold the angular look that comes from blasting.

[nuno81291]

Not my photos but here's some roundish New England granite.

https://photos.smugmug.com/Landscapes/Land-and-Sea/i-HmZBZ8s/7/L/crawford_notch_fall_color_2401-Edit-2-L.jpg
https://upload.wikimedia.org/wikipedia/commons/a/a0/MtLiberty.jpg
http://image.shutterstock.com/z/stock-photo-exposed-granite-of-the-summit-of-mt-cardigan-near-grafton-new-hampshire-with-a-view-of-395853991.jpg

[peteski]

I guess driving up and down on I 93 and Everett Turnpike skews my perception in the appearance of granite. All I see it the faces created by blasting - so it sticks in my mind.

[nkalanaga]

Massive granite often weathers to round surfaces.  Homestake Pass in Montana is one good example, with the NP and I-90 going through the Boulder Batholith.

[OldEastRR]

Most of my rock areas will be along a river/creek scene, and a few outcroppings nearby. There will be a large mill on the river bank, so I found a picture of such a scene. The bedding planes and composition of the rock would not change. As for the small outcroppings it's helpful to know they are heavily vegetated. so I probably won't "weather" them very much.
It's safe to say any rock along or in a watercourse would be rather worn.

[peteski]

Most of my rock areas will be along a river/creek scene, and a few outcroppings nearby. There will be a large mill on the river bank, so I found a picture of such a scene:

Is that the Merrimack river in Manchester? It looks familiar (but I guess the scene could be anywhere where there are brick mills and a river).

[OldEastRR]

Not my photos but here's some roundish New England granite.

https://photos.smugmug.com/Landscapes/Land-and-Sea/i-HmZBZ8s/7/L/crawford_notch_fall_color_2401-Edit-2-L.jpg
https://upload.wikimedia.org/wikipedia/commons/a/a0/MtLiberty.jpg
http://image.shutterstock.com/z/stock-photo-exposed-granite-of-the-summit-of-mt-cardigan-near-grafton-new-hampshire-with-a-view-of-395853991.jpg

Yeah, that's the look I'm going for. I don't have a specific scene in mind, I'm going from my memories of traveling through NE several times in the past. There is a softer edge to these rocks than what one gets from model casting molds.

[Missaberoad]

Those kinds of rock formations are pretty common across the Canadian Shield (or Precambrian shield to include the New England part...  )

Just remember that most rock cuts along railroad tracks were blasted so the cuts will still be rough and jagged...

Eagle rock in Redditt Ontario is my favorite example...

[nuno81291]

I missed the watercourse part of the equation. Is it smooth? I guess thats in the eye of the beholder.

[peteski]

I missed the watercourse part of the equation. Is it smooth? I guess thats in the eye of the beholder.

Nothing to apologize for - that detail was not mentioned until after your first reply.