In celebration of Darwin’s birthday I told my children about who Darwin was, about his trip on the Beagle, and I tried to explain to them — using Lego blocks — the theory of evolution. We ended up talking about fossils and decided to go to look for fossils on the weekend. I had never gone in search of fossils before and I didn’t know what to expect. But it turned out to be a success! It took us no more than ten minutes to find the first fossil and about twice as long to find a perfect fossil of a seashell.
The next day my son took the fossil to school. To my surprise his English teacher couldn’t believe that one can find a fossil of a seashell on top of a mountain (Hilton Falls in Milton, Ontario) a few hours from Toronto. She asked him if he knew how the seashell got here all the way from the ocean. And he knew it. His science teacher thought it to be a great idea to go on a school trip with the class to look for fossils.
If you have young kids, go look for fossils! If you have other ideas how to make science fun for kids, let me know.
George, your tale piqued my curiosity, so I had a quick look at a geological map of Ontario. It turns out that the area you found those fossils in is Ordovician sedimentary. Those seashells are roughly 450 million years old. Also, you might want to set your kids loose identifying them, because they are probably not at all like modern seashells. The most likely shape is a kind of spirally cone—is that what you found?
Fossils are neat, and they’re even neater when you can connect them to a story.
George, your tale piqued my curiosity, so I had a quick look at a geological map of Ontario. It turns out that the area you found those fossils in is Ordovician sedimentary. Those seashells are roughly 450 million years old. Also, you might want to set your kids loose identifying them, because they are probably not at all like modern seashells. The most likely shape is a kind of spirally cone—is that what you found?
Fossils are neat, and they’re even neater when you can connect them to a story.
Chris,
The one my son took to school looked like a typical modern seashell:
We did find one that looked like the top of a spirally-cone seashell, but the ground was frozen and we were unable to dig it out. We marked it in a map we made, and plan to go back as soon as the weather warms up.
But thanks for the advice: identifying the fossils is a great idea! Perhaps we need a bigger collection before we do that.
Strange; I’m pretty sure that the shell you illustrate is not Ordovician. This is strange
Chris,
How do you know which period the shell might belong to? The mountain we visited is literarily cut it in half by a river that runs through it, and it is vividly formed by many different layers. Wouldn’t each layer correspond to a different time period?
(Aviculopecten subcardiformis; an extinct
pectenoid bivalve from the Logan Formation
(Lower Carboniferous) of Wooster, Ohio
(external mold).)
Aviculopecten is an extinct genus of bivalve mollusc that lived from the Early Devonian to the Late Triassic in Asia, Australia, Europe, North America, and South America. Bivalve
That would date your find from 420-300 million years old. Just based on some google searches I found there are fossils within 200 km of your find dating to the Devonian period which would make your shell 360-300 million years old. It seems these types of fossils stretch from parts of ohio, ontario, and delaware. Aviculopecten in Ontario
My suggestion would be to do some taxonomy and figure out what species it is (it is definitely in the order Pterioida). Then do some geological research and see if you can find a story that fits.
How do you know which period the shell might belong to? The mountain we visited is literarily cut it in half by a river that runs through it, and it is vividly formed by many different layers. Wouldn’t each layer correspond to a different time period?
Easy. I looked up a geological map of Ontario and discovered that the entire area around there is Ordovician sediments. Yes, there are many layers, but the Ordovician lasted some 50 million years, so there’s plenty of room for hundreds of feet of sediments.
Easy. I looked up a geological map of Ontario and discovered that the entire area around there is Ordovician sediments. Yes, there are many layers, but the Ordovician lasted some 50 million years, so there’s plenty of room for hundreds of feet of sediments.
It’s a pretty rough map, but the geology of that area seems pretty simple (below the glacial surface stuff): Ordovician around Toronto, Silurian (a bit later than Ordovician) to the southwest, and Devonian (even younger) further southwest.
By the way, there are a lot of really old rocks in your area. On the map, those orange and green splotchy areas to the northeast of Toronto are all neoproterozoic to mesoproterozoic, which makes them about a billion years old. Even more interesting is that greenish section around Moosonee, about 500 miles north of Toronto: those rocks are Mesoarchaen, which makes them 3 billion years old! That is IMMENSELY old; very very few rocks of that age survive. There won’t be any fossils, of course, but the rocks themselves are still interesting. They are all metamorphosed rocks, originally igneous or sedimentary, so they won’t show much structure. My area is metamorphosed igneous rocks only 175 million years old.
Canada has the oldest rocks in North America. There are some really fascinating rocks out there.
Chris, thank you for all the information. Those orange and green spots are located in Algonquin Park, a place we visit at least twice a year. I know what I’ll be doing on my next trip there!
BTW, my son just told me that everybody in his classroom wants to become an archeologist now. Call me Carl Sagan!
