Thanks for sharing your response. I agree with you the rate of change does seem to be slow upon the landscape for any changes to these features. Here are a few examples to consider that may indicate water has washed over some of the features:

Circle ground glyph
38.279712, -110.590056

Glyph
38.251744, -110.632175

Two circle glyph
38.250383, -110.640410

Circle ground glyph
38.231013, -110.575770

Two circles with main line through middle
38.153269, -110.568176
-This one is like many of the circles and glyphs in close proximity to a water hole/well feature almost like a cenote. Seeing this is in a pretty remote location, it may in fact be an ancient water hole and many are dotted around these placemarks.

Circles
38.153571, -110.550588

Strange somewhat rectangular pattern
38.151606, -110.533764

Four line pattern
38.102420, -110.605973

Four line pattern
38.094162, -110.621288
-Notice the two lines leading off to the North and North East seem to have been washed out by water flow.

There are many more examples where water seems to have been responsible for the break down of some of the glyph features.

It's my gut feeling that Utah is not the only place where features like this are located. I'm searching other states out West now to find any similar features. There are a few items in Oregon that both I and Ed have marked as potentially ancient spiral features, one was not on the Terraserver older imagery but a few others are. Circular Features: Oregon The Hart Mountain concentric circle does not show up on the old terraserver imagery but the other spirals further North do show up: 3 large spirals Oregon I've contacted several archaeologists in Oregon about these but they seem to think that ranchers created them but my argument is if ranchers created them why aren't they everywhere?

Ed has pointed out that if you zoom out on the placemarks and take a look at the bigger picture they seem to be making a larger pattern on the landscape and this is a possible theory he has as to why they were created. We have done some initial research into petroglyphs in Utah and there are several examples of circles and lines that are similar to Ed's Glyphs.

Most of the petroglyph examples aren't located near Ed's placemarks but still worthy of some notice:

Parowan Gap Petroglyphs 1


Parowan Gap Petroglyphs 2


Fremont Indian Petroglyphs


Parowan Gap Petroglyphs 3


Parowan Gap Petroglyphs 4


Parowan Gap Petroglyphs 5


Parowan Gap Petroglyphs 6
-This one actually has some circular features connected by a line, far left side.

Hopefully someone will eventually take enough interest to make some potential discoveries with the information contained in the anomaly collection.