rock with fossil?

your pics arent too clear but dont you think that the rock with the coralline stuff is actually "Spat" of which a fairly recent coral hd been establishing its colony?

I have no ideas just guesses , if you could try to clear up the photos and put a peso next to the pic for scale.

I am not familiarized with coral, so I cannot say, the place where I found it is a landlocked, high mountain, relatively far from the sea, 30km or more. In addition there was no evidence in the outer look of the rock, when I broke it was then when this bony material became visible. I took a few more photos with a peso(you can note the coin has a "N" before the sign of pesos and the number 1, it has it because is a coin from 1994. In 1993 and in 1994 these new coins were called "new pesos", from 1995 and afterwards the "N" was dropped in all coins) as a scale so it could clear up a bit.
http://www.flickr.com/photos/51986587@N04/8464843989/sizes/k/in/set-72157632734267449
http://www.flickr.com/photos/51986587@N04/8465934088/sizes/k/in/set-72157632734267449
http://www.flickr.com/photos/51986587@N04/8464841267/sizes/k/in/set-72157632734267449
http://www.flickr.com/photos/51986587@N04/8464830383/sizes/k/in/set-72157632734267449
http://www.flickr.com/photos/51986587@N04/8464870311/sizes/k/in/set-72157632734267449
http://www.flickr.com/photos/51986587@N04/8465972354/sizes/k/in/set-72157632734267449
http://www.flickr.com/photos/51986587@N04/8465997896/sizes/k/in/set-72157632734267449
http://www.flickr.com/photos/51986587@N04/8465960246/sizes/k/in/set-72157632734267449
http://www.flickr.com/photos/51986587@N04/8465957948/sizes/k/in/set-72157632734267449

boy, it could be a bone cross section but I swear I see some teeny crystals on one of the specimens. So, It also may be what we call a druse(which are tiny crystals in a mat). So that would make the "bone" cross sectional stuff maybe a "scoria" or a pumice like rock that was ejected from an old volcano. DO you know anything about the geology of the area? What part of mexico was it in an maybe I can fnd the geologic map. Do you find stuff like "Apache tears " or obsidian flakes or rocks nearby?

The area is near the city of Mazatlan, I think is part of the Sierra Madre Occidental mountainous chain. Indeed, I remembered the soil of the farming fields around looked like volcanic ashes, there were many fragments of obsidian and pumice rocks over them. Thanks farmerman.

Then I think its more a scoria or a pumice. You have to really consider the geology of the area youre in. Is the rock part of the various outcrops or is it showing evidence of being rounded and moved some distance.

Rock and minerals always have a context where you can determine where their sources are and where there may be more of the same stuff

I was so exited that I didn't realize it could be anything else, lol.