Unique fossils

Hey guys,

I'm doing a project on unique fossils, and I'm trying to come up with a list of examples.

So far I have the fluorescing bones of _Seismosaurus hallorum_ and the magnesium rich bones of Black Beauty, and the pyrite infested bones of the Bernissart iguanodonts.

Does anyone else know offhand, of any unique fossils (in terms of composition) ?

Alberta amonite.

Opalised tibia of Kakuru kujani.

1. At one time there were some opalized invertebrates being sold from Australia. Not gem quality although some of them had opalescent layers. They proably weren't uncommon as the price was just a few US dollars per clam.

2. There was a locality called, as I recall, Scioto Bar on the Ohio River where paleozoic fossils molds hade been filled with some improbable mineral

Placenticeras Meeki. The shell lining gets replaced by aragonite. It is turned into a gemstone called (big coincidence) ammolite, which the Canada Fossil Co. has a monopoloy on mining in Alberta at its Korite quarry. Canada Fossil convinced the Alberta gov't some years ago to have Placenticeras fossils declared a mineral as opposed to a fossil so they could more easily skirt export/conservation laws and do as they wished.

Also, you can find various ammonites in Alberta that have been entirely replaced by pyrite (dactyloceras, I believe usually). Require care as they will oxidize.

Both are common in rock shops around southern Alberta.

I'm not sure who Black Beauty is, but the skull of

'> '> 1. At one time there were some opalized invertebrates being sold from '> Australia. Not gem quality although some of them had opalescent '> layers. They proably weren't uncommon as the price was just a few US '> dollars per clam. ' ' I picked up some of these at the Opal Museum in Sydney ' this summer. The ones I bought weren't gem quality, but ' gem-quality opalized fossils can be found

FWIW, Fruita, Mesa Cy, CO, In Devil's Canyon. 2km S on Colorado National Monument Road, cross River, Turn W 1km to fork. Left at fork, 2km to fork left at fork 1km then 1km N

Yes, this is a truly world-class locality. The fossil-bearing area has been heavily collected over the past two decades, in particular, but a dwindling select few hotspots still produce rare to common distinctive arthropod-bearing concretions/nodules in the Middle Miocene Barstow Formation. From time to time, in the past, I used get the 'Barstow Bug' and start another round of concretion dissolving (I have remaining a few of the fossiliferous calcareous concretions that I collected several years ago): loads of fully three-dimensional midge pupae, water beetle larvae, and the remains of soft-bodied fairy shrimp, primarily, appear in the insoluble acid-bath residues

Thanks to all who chimed in with the unique fossil examples. They came in handy for my report.