Specimen: Geisenoceras Fossil
Genus/Species: Geisenoceras
Era: Devonian
Age: 400 Ma
Location: Morocco
Size: 1"-2"
Notes:
This table contains the geological time periods of the past 2.5 billion years on Earth to aid in understanding age immense age of these fossils.
(Ma = Mega-annum = 1,000,000 years)| EON | ERA | PERIOD | EXTENT (Ma) | DURATION (Ma) |
|---|---|---|---|---|
| Phanerozoic | Cenozoic | Quaternary | 2.588–Present | 2.588+ |
| Neogene | 23.03–2.588 | 20.4 | ||
| Paleogene | 66.0–23.03 | 42.9 | ||
| Mesozoic | Cretaceous | 145.5–66.0 | 79.5 | |
| Jurassic | 201.3–145.0 | 56.3 | ||
| Triassic | 252.17–201.3 | 50.9 | ||
| Paleozoic | Permian | 298.9–252.17 | 46.7 | |
| Carboniferous | 358.9–298.9 | 60 | ||
| Devonian | 419.2–358.9 | 60.3 | ||
| Silurian | 443.4–419.2 | 24.2 | ||
| Ordovician | 485.4–443.4 | 42 | ||
| Cambrian | 541.0–485.4 | 55.6 | ||
| Proterozoic | Neoproterozoic | Ediacaran | 635.0–541.0 | 94 |
| Cryogenian | 850–635 | 215 | ||
| Tonian | 1,000–850 | 150 | ||
| Mesoproterozoic | Stenian | 1,200–1,000 | 200 | |
| Ectasian | 1,400–1,200 | 200 | ||
| Calymmian | 1,600–1,400 | 200 | ||
| Paleoproterozoic | Statherian | 1,800–1,600 | 200 | |
| Orosirian | 2,050–1,800 | 250 | ||
| Rhyacian | 2,300–2,050 | 250 | ||
| Siderian | 2,500–2,300 | 200 | ||
GEISENOCERAS
Geisenoceras is an extinct cephalopod, similar to a squid with a long, pointed shell that lived during the Devonian period around 400 million years ago.
The lighter areas were cavities in its shell that it used for bouyancy and propusion in the water. The dark portion is the surrounding rock that the fossil was embedded in.
For many years, scientists thought this and many similar specimens were all one species called Orthoceras regulare.
But it was eventually discovered that there were in fact over 2,500 unique, conical-shelled, nautiloid species in the fossil record, and sorting the taxonomic record became quite an intensive undertaking.
This is an example of scientific progress. Often when we hear about scientists being wrong, it’s being reported in the news as a failure. On the contrary, being proven wrong presents an opportunity to learn something new. Progress can only occur where we have room to grow, and finding faults in our thinking illuminates areas of potential advances, but only if we adapt to the new information.
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