How To Tell Fossil Bone From Wood, Etc.

[tracer]

well, this post will be very rudimentary info for some, but i thought i'd throw out some pictures of typical things that might be found in a mixed-bag waterway environment for those who might at times have difficulty telling fossil bone from other stuff, etc.

sooo...here's some stuff.

it's really a number of different kinds of things. so let's look at the stuff more closely.

this stuff is fossil bone. a major giveaway of what it is can be found on broken edges, where the inner "spongy" bone is exposed. sometimes that isn't exposed, and sometimes it's all worn away, but i can tell just from the "stickiness" when i slide my fingers along it that it's bone, if there's any humidity in the air. and i can feel the extra weight of added minerals if it's fossilized, and i push my fingernail against the spongy bone. if it crunches easily, it's not very mineralized. if it doesn't crunch, then it's pretty mineralized. there are visual cues too, but occasionally we pick up one that looks like a fossil and find that it's light and crunches easily, which for some reason triggers tj's throwing reflex, and he gives it a sail.

this stuff isn't found just anywhere, i guess, but it's mudstone. it's interesting, but it's not a fossil and to the best of my knowledge only exists for tj to throw it.

this stuff is petrified wood, except for the two corners of bone peeking in on the right-hand side of the picture. the shapes and fracture patterns of petrified wood are something that you over time just learn and you don't even need to bend down to see the grain structure to know what it is. it seems like the waterways downstream from the eocene in coastal texas are full of this stuff. at first i went looking for it. now it seems to follow me wherever i go. some well-silicified fossil bone vaguely resembles fossil wood on the outside and seems to have a "grain" of sorts, but it's not as linear and it fractures more randomly.

ok, well, here's a closeup of some stuff that's labeled. fossilized turtle shell's kind of a common thing, but some aren't too familiar with how it looks. soft-shelled turtle shell has a distinctive pattern on it. sometimes you find the turtle shell pieces lying with the "outside" side face down, and just see a rib attachment and some striations on the side facing you. there were some pretty ginormous land tortoises back when also, and you can find some very thick pieces of shell in some of the places we go looking for things. broken turtle shell has that spongy look on the edges like bone.

anyway, i'm getting tired of this post, so you probably are too, huh? remember, newer stuff can usually be found amongst the older stuff when you're around current or former waterways where things got mixed up over the years. so you can find pieces of mammoth in the cretaceous. the big piece of bone in the picture is one tj found, and he wishes it could ID itself. it's too robust to be from anything currently roaming the area, so he dubbed it a piece of elephant. could be that, or maybe giant sloth or mastodon or who knows? we always take our imaginations in the field with us, which is a major part of why we have such a good time.

[grandpa]

Tracer, that's a very good tutorial.

Maybe you or someone else can take it another step further. I seem to have a devil of a time telling bison teeth from fossil cow teeth from modern cow teeth. Any help would be appreciated.

[tracer]

grandpa - unfortunately, you pose a very difficult ID issue to deal with, in my mind. i think this link has been posted before, but here's a start on tooth id issues. link

but that doesn't help at all really with the issue you posed. as far as i'm concerned, i've become confident in my ability to tell old teeth from recent ones. especially if it's standing there mooing at me.

tooth enamel is very hard and very dense. it is already comprised of approximately 95% mineral (hydroxyapatite) when the animal dies. so there isn't a bunch of room in the enamel for the processes involved in "fossilization" to occur. so when the tooth enamel has changed to glorious colors, and especially if it's got hard matrix adhering to it, that starts being good indications that it's a fossil. the best bet for being sure on bison is if the teeth are found with enough of the jawbone to tell from the robustness, or obviously if they're in situ with other parts of the animal. but even then, i was having enough problems differentiating post-cranial bones from bos and bison apart that i bought a book written just for that purpose.

having said all that - i'm a practical man. if i take it home, then by gosh it's bison until you prove otherwise.

[Ron E.]

tooth enamel is very hard and very dense. it is already comprised of approximately 95% mineral (hydroxyapatite) when the animal dies. so there isn't a bunch of room in the enamel for the processes involved in "fossilization" to occur. so when the tooth enamel has changed to glorious colors, and especially if it's got hard matrix adhering to it, that starts being good indications that it's a fossil.

A simple statement that is profound, and is probably hidden on page 498 of a college textbook.

Thanks, T.

[grandpa]

having said all that - i'm a practical man. if i take it home, then by gosh it's bison until you prove otherwise.

Alright, that's what I do too. "I found it, I get to name it!"

[Seldom]

Thanks Tracer good info

[jeepinthemud]

Good reference page, T-man!

Two thumbs up!