What Creatures Can You Identify In This Fossilized Sea Floor?

A fossilized piece of the sea floor is a glimpse into an ecosystem long-gone, if only you know how to look at it. Read on to learn about the long-dead bryozoans, crinoids, brachiopods, gastropods, and even trilobites in this rock.

Top image: Fossilized section of sea floor. Credit: ottermann

Otters Oddities

If you squint, it kind of looks like one of those tollhouse cookie bars your mom would make when she wanted cookies, but was feeling a wee bit lazy, so she just dumped them onto a baking sheet and made bars instead.

I said you had to squint. And it only 'sort of' looked like them. Stop busting my chops. It's late and I'm hungry. As a matter of fact, I'm cooking something that wouldn't look too out of place on that slab there. I'm baking some shrimp in garlic and butter.

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Ok, it would look out of place to see cooked shrimp on that fossil. But if there was a fossil of a shrimp it wouldn't be strange, would it? Yes. Yes it would. Because that fossil is from the sea floor from hundreds of millions of years ago. Before there were shrimp. Well, shrimp that we would recognize, at least. The Anomalocaris is related to the shrimp. But you'd be freaked out if you saw one. I'll post about them some other time, though.

But I'm getting ahead of myself. Today is Friday which means it's time for Friday Rocks! If you haven't guessed it by now, this is the day when I feature fossils. You know, rock with dead stuff.

This week I am showing a couple of examples of sea floor plates. If you were to dive to the ocean floor, you wouldn't see just barren muck. (well, you might...depending on where you look). But if you weren't in a barren part of the ocean, you'd see all sorts of things on the sea floor. Plants, animals, dead things. And that's what these fossils are. Basically snapshots of what that particular part of the sea floor looked like at a particular moment in time, hundreds of millions of years ago.

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In the above picture, you can see many different fossils. If you click to enlarge it, you'll see more than you thought was there. The following picture doesn't have as much on it, but what it does have is neat.

Sea floor plates are interesting because it gives you an idea of the diversity of life. With many types of fossils, like dinosaurs for example, we rarely find different specimens together. We know what dinosaurs lived with each other mainly by association. We find bones in the same layers of fossiliferous strata that all dates to the same period. But dinosaurs that are found say, 100 feet apart, might have lived separated by 5 million years. But with sea floor plates like these, we know these fossils lived at the same time. Otherwise the older ones would have rotted away.

What would make these fossils more interesting? Why, my lame attempts at photo manipulation of course!

  1. This is a Bryozoan known as an Archimedes. It get's it's name because of it's shape. You see how it resembles a screw? In life, this spiral would have been it's spine. But a bryozoan isn't a single creature. It's actually a colony, sort of like a coral. They are filter feeders. Individual bryozoan group together into clusters called Zooids. These zooids will take on a specialized role. Some will be in charge of feeding, while others are in charge of waste disposal.
  2. This is a piece of Crinoid stem laying on it's side. If you'll recall, crinoids look like plants, but are actually animals. I have another crinoid fossil I'll be showing in a later post that is interesting because the crinoid is gone and all that remains is a cast of what the interior of it's stem looked like.
  3. This is also a Bryozoan. Unlike the Archimedes, this is a part of a bryozoan that would have been part of the feeding zooid. That's why it looks like a net. It would filter food out of the water using this structure.
  4. Huh....would you look at that. There is no number 4 on the picture. Ah well....mistakes were made...
  5. This is a Brachiopod. Brachiopods were shellfish, much like the bivalve I showed last week. The difference between the two is, in a bivalve they are symmetrical on a top/bottom axis. Brachiopods are symmetrical on a left/right axis.
  6. This is a section of a Crinoid stem. If you sliced #2 so you could put it on a pizza, it would look similar to this.

Be sure you enlarge the picture so you can see more detail.

  1. This is a Bryozoan. This zooid acted like a stem. In life, the Archimedes would have looked similar to this.
  2. This is a cross section of a Trilobite thorax. If you'll recall, trilobites got their name because of their three sections, the Cephalon, Thorax and Pygidium, (head, body and tail from front to back). Remember though, I also told you they had three lobes going from left to right, the Axial lobe in the middle and the Pleural lobes to the left and right. This is the Axial lobe.
  3. These are the Pleural lobes. The legs would have stick out to either side of the pleural lobes, while the main digestive system would have been tucked up in the axial lobe.
  4. More Trilobite cross section. This one only has the axial lobe and one of the pleural lobes.
  5. This is a Trilobite Pygidium. Judging by it's location and size, it's probably the pygidium that goes to the trilobite from # 2-3. This is most likely from a molt rather than a victim of a predator.
  6. These are Bryozoans in a pile, like firewood. But since they were under water, you couldn't light them on fire. Unless you're SpongeBob or Patrick. They could lite fires under water.
  7. This appears to be a Gastropod. I say appears to be because I am not an expert on Bryozoans or Gastropods. It could be an Echinoderm, but I don't think it is. I really think it's a Gastropod. I would have to have it evaluated by someone more knowledgeable than I to be certain, though. A Gastropod is a snail. And yes, you could probably eat them. Although I don't know why anyone eats snails. All they are are cooked boogers in a lot of butter.
  8. This is an Archimedes cross section. You can see the spiral, (you're looking straight down at it), surrounded by it's outer skin.

One of the reasons I really like the second example shown is because of the orientation of some of the examples. The cross section of the trilobite is very well defined, and the archimedes is actually quite well preserved also.

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I do have several more examples of sea floor plates. And while they all have some nice features, I have shown what I consider to be my two best examples. Maybe someday I'll take all my fossils and group them together to take a picture of all of them at once to give people an idea of the size of my collection. But than again.....that would be a pain in the butt. So maybe I wont. We'll see.

Anyway, next week, if I remember, I'll tell you all about some of the freaky creatures I have. Creatures from the very beginning of visible life, 560 million years ago.

Have a splendiferous weekend!