Fossil Or Not?

[tlatoanitzin]

There is a bed of this rock in a mountain, I took off a chunk of it with my hand and carried home, when staying in home I took the rock and separated with my hands in halves very easily, then I observed that it had this kind of biological features or what it seemed to me, in both halves. The first I thought it was some kind of root that was got into the rock, but then I remembered that the chunk was shut. I noted that it had two layers of this material, one different to the other, I ended up destroying one layer, in order to photograph the one with more remarkable features. I would like to know if the biological features are present because the chunk of rock is a fossil or if it is just a mineral.

http://www.flickr.com/photos/51986587@N04/sets/72157632716535471/

[Auspex]

I think the root mat is modern, grown into the weak plane between the layers.

If I could enlarge the picture for details, I might be able to either retract or confirm my initial impression.

[Scylla]

I don't think I see any fossils here, but the net-like pattern is interesting. Which mountain? The local geology will be a big help in deciding if it could be a fossil or not.

[tlatoanitzin]

Flicker doesn't display large pictures by default, you must click over the picture, click open in new window, click over the picture again, then in the upper right-most corner click more sizes and click over the larger one, and it will display one like this, it is tedious, I know. I found it in the same place where I had found one brachiopod stone. It is a granitoid mountain with semi arid weather, very close to San Diego, California. In the region grows certain types of shrubs so I don't dismiss the modern root hypothesis.

[pleecan]

looks like modern roots also... as suggested by Auspex...