1. I have Science homework and I'm REALLY stuck! Someone help me please!

There are 3 (not photos, just black and white drawings) pictures of fossils. A is just a plain swirly fossil with no markings on it. B is the same swirly fossil but it has a few markings on it and a few dents in the side. C has loads of markings on it and loads of dents round the side.

Here are the questions:

a) Which fossil (A, B or C) can give us the most precise age of a rock?
b) Which fossil is oldest?

Then there is a picure with 8 layers of rock, 8 being the closest to the ground. Layer 1 is bricks, layer 2 (sorry it's not very clear, but they're just black and white drawings) has lots of little specks of something in it, layer 3 has diagonal lines to the right, layer 4 has loads and loads of little dots, layer 5 had diagonal lines to the right, layer 6 has little twigs or something in it, layer 7 has these half circles with lines coming out of them and layer 8 has little dots in it. Sorry about the bad description.

Anyway, more questions:

c) Which layers of rock (1 to 8) could contain fossil A?
d) Which layers of rock could contain fossils A and B?
e) Why can we get more precise information about a rock containing fossils A, B and C?

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3. It is quite impossible for anyone to assist you based on the weak descriptions you have provided. Swirly fossil?? Dents??

We need to see the actual pictures. From your descriptions it sounds as though they depict the same fossil, successively enhanced. But if we could see the actual pictures it may turn out we are looking at three separate fossils. Trilobite? Chambered nautilus? Club moss? Neanderthal skull? Who can tell. Maybe you can do better.

4. The answer to e, I think, is that if you have a rock with 3 different fossils in it, that rock would have to have been formed when all three species were alive, which narrows down the time period.

I suspect the first thing you will have to do is to identify the species, which we can't do from your descriptions.

5. What has this to do with chemistry?

6. Nothing. I've moved it to Earth Science.

7. Sorry about the bad descriptions! The "swirly fossil" is one of those really common fossils, the ones that look a bit like a snail's shell.

8. you wouldn't happen to have their binomial name ?

9. So my above guess was right! A chambered nautilus! Check out this link and see if you agree:

http://en.wikipedia.org/wiki/Nautilus

Now tell us if all three pictures are all of the same animal. If so, give us a clearer picture of their differences; none of those "dents."

10. if the smooth one is a nautilus then at least one of the "dented" ones is likely to be an ammonite, which are obviously far more useful as zone fossils than the nautilus

11. Originally Posted by forgotten606

a) Which fossil (A, B or C) can give us the most precise age of a rock?
b) Which fossil is oldest?
A) A good zone fossil is:
-abundant
-well preserved
-limited in duration of existance
-easily distinguishable from similar vareities

Does the question give you any information on any of these?

B) Sounds like you are talking about ammonites or goniatites. These tended to develop more and more complex suture lines as time went on if memory serves, so the one with the simplest sutures (if you can see them) should be oldest.

12. ok thanx

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