Estonian Fossils part III: The Pakri Peninsula
Pakri is a cliff area in northern Estonia. It has a lighthouse that is easily reached by road and is a good place to watch the sunset. Before reaching the lighthouse, there is an access with stairs to go down to the beach. There you can find the stones that have been dislodged and left visible.


In Pakri, in addition to the typical fossils that are easy to see in Estonia, there are a large number and variety of other different and mysterious types of fossils.
You can find more about fossils in Estonia in Estonian Fossils part I and Estonian Fossils part II: the rubble.

Among the most curious you can find:
- Receptacle
- Ripple marks
- Rock spheres
What are each of them?
Receptacles
They have long been a mystery. Both its origin and its habitat are the subject of disagreements in the scientific community. What there is agreement on is that they belong to the Ordovician period (those found in Estonia), and that they can be found on all continents except Antarctica.
Its structure is reminiscent of that of the sunflower and that is why it has sometimes been called “sunflower coral.” They have a “double spiral radiating pattern.” And they are medium in size.
More info:
https://en.wikipedia.org/wiki/Receptaculites
Ripple marks
They are the result of sedimentation agitated by a current of water, and when they are fossilized like these they are also evidence that in a very distant period in time that area was submerged under water.

More info:
https://en.wikipedia.org/wiki/Ripple_marks
Rock spheres
I have not been able to find much information about them, only that it is a layer of pyritized sandstone in which these pebbles are found. If you have more information about what it is, don’t hesitate to tell me.
Reference link:
https://geoloogia.info/en/file/14517/