Welcome back! Time for part two of fossil types. So, you remember what type of fossil we discussed last time? That’s right, casts. These lead directly onto the next type of fossil – in fact, you rarely get one without the other. These are moulds.
You can easily replicate a mould fossil. You may even remember it from last time. If you want to re-make one, all you need is:
- Some clay or some damp sand.
- A ‘fossil’ to create a mould, could be a shell or toy animal.
What you are basically doing is creating the first part of a cast, but not filling it in with anything, like you did with the plaster of Paris last time. Simply take the damp sand or clay and form it into a ball. Press down to flatten it a bit, then push your shell/toy into it firmly. Take it out, and hey presto! One replicate mould fossil!
So, in the real world, mould fossils are made two ways. Either, a creature gets caught up and covered in sediment. The sediment covers up and sets but does not penetrate the animal (that’s for next week 😉). The shell/animal then gets destroyed, but no other sediment infills the hole left. When broken open, you find a mould fossil. This is the rarer of the two ways though. The other is similar, but with one twist. Basically, you make a cast fossil. Now, there already is a mould fossil in there! Remember when you finished your cast fossil, and you took the cast out of the clay mould. In one hand you had the cast, in the other the mould. So, a mould fossil is basically the imprint of where a fossil (and hence an animal) once was but has no remains of that actual animal – just its imprint.
You can see some example of mould fossils, some of them have cast and mould together, so you can see the difference. So that’s part two! The next time we visit types of fossils, we will be discussing when the minerals actually go into the animal to preserve…… See you soon!
To find out more about types of fossils, visit www.creationresearch.net
As always, you are very welcome to visit the Genesis Museum of Creation Research – www.genesismuseumofcreation.com
Video showing a rare fossil ammonite from the Himalayas in Nepal. You can see it open up to show the two types of fossils, the cast and the mould
Another video showing a fossil shell inside a nodule – again, the cast and the mould is present.