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Potential to Kinetic

Applying What We've Learned
Fossil Interpretations

Adapted from Solving the Puzzle, Teacher's Guide to Evolution - a journey into where we're from, and where we're going, a project of WGBH television and Clear Blue Sky Productions.


Observe and describe fossils and sediments from a paleontological sample and, based on what we've learned this morning about grains, transport, and energy, make interpretations and hypotheses about its environmental setting.


Dominican Republic fossiliferous, silty sandstone

Locality 52700-2E
Miocene (about 6 million years old)
Cercado Formation, Rio Gurabo
Collected by C. Tang, Summer 2000


Every group will receive a random sub-sample from this bulk fossil sample, which was collected from one interval of strata.

PART 1 (5 minutes)

Take five minutes for individual observations, using a hand lens if necessary. Write down your observations of the fossils and sediment. Do not include interpretations, only note descriptions and add quick sketches if you find them useful.

PART 2 (15 minutes)

Share your observations with your group. Based on the observations and the information you learned earlier, what can you hypothesize or interpret about the sample?

PART 3 (10 minutes)

Come together as a class to share evidence for your interpretations. What other types of evidence would you need to test the hypotheses? Why would this information be important for paleontological and geological studies?

Teacher Results:

  • Diversity is high. There are even the microfossils, called foraminifera.

  • It must be an aquatic source as there are so many shells.

  • Many of the fossils are intact.

  • It contains some unfamiliar shells. Also magnetite.

  • High concentration of fossils and very little sorting.

Interpretation and Discussion:

There must be very little wave energy, because the shells are not broken up.

But what about the fine grains of sediment? Does that mean high wave energy, or it is just further away from the source?

Where were they found? If it is not the original source and it was transported, then shouldn't the shells be broken?

The fossils were deposited about 6 million years ago and have now been pushed up. Must have been a rather shallow deposition site as there is such a diversity of shells. You would not expect such diversity at great depths.


We can look at fossils just as we look at grains of sand; the history is there to be interpreted.

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