At GZ, you will find a series of several large rocks that are used to prevent people from driving into the park. These rocks are no ordinary rocks - they contain a collection of very large fossils, larger than most of the others found in the area.
There are three types of fossils found at GZ - Fossil Impressions, Trace Fossils and Body Fossils
Fossil impressions
Fossil impressions are imprints or indented marks in the stone, caused by a item pressing into the mud, silt or sand as it hardened into rock. Over time, organic matter decays until there is nothing left ecept the impression of the item. The empty space in the shape of the plant or animal is referred to as a cast. Often these casts show the details of the item, and typically withstand the elements fairly well, showing minmal signs of erosion.
Fossil impressions are found preserved in sedimentary rock, normally clay and shale.
Trace Fossils
Also known as ichnofossils, Trace fossils include things such as footprints, tracks, burrows, and fossilized feces. These fossils show how prehistoric creatures lived, but are not actually a part of the prehistoric creature itself.
Body Fossils
Body fossils are the remains of plants, animals or bacteria from prehistoric times that have been preserved either partially or wholy intact, giving us a direct visual into what these creatures looked like millions of years ago. Body fossils also include teeth, bones, skin, eggs, leaves, wood and even bark. In Ontario’s sedimentary limestone, it is common to spot fossilized shells and crinoids in limestone blocks.
But why are these fossils different?
When you arrive at GZ, you will notice that these fossils appear much larger than most other fossils in Ontario. When I arrived at GZ, I was amazed at the size, when compared to other Earthcaches I have done in the area and along the shores of Lake Erie and Lake Ontario.
But, why are these particular fossils so large?
Better Oxygen
First, several studies hypothesize that environmental factors, such as higher oxygen content in the air, contribute to expansion in North America. This is from a study published in 2019 from researchers from Rensselaer Polytechnic Institute and the University of Texas Austin. They used a new technique to analyze tiny amounts of gas trapped inside 215-million-year-old rocks from what is now North America.
Cope's Rule
Then there's Cope's Rule, which is a hypothesis that says animals in evolving lineages tend to get larger over time. This would suggest that the fossils before you are from about 400 million years ago, rather than 700 million years ago like some other stones in the area.
Light Bones and Air Sacs
Finally, other evidence points to why prehistoric animals grew so massive could be because of their bones and lungs. Some species, such as the pterosaurs started out small, but some then ballooned to unbelievable proportions. This could have been due in part to a highly effective flow-through respiratory system, which allowed them the ability to sustain flight, combined with an extremely light bone density (nearly half of what would be considered normal in most land mammals nowadays). Some prehistoric creatures have shown to have very light yet extremely durable exoskeletons, weighing (on average) less than a third of the weight of comparable bones. Without excessive and proportional weight, creatures would have been able to grow rapidly without risking bone breakage and stress on the body like today's animals (especially long legged animals like horses or giraffes).
These three reasons combine to create a series of large fossils. Similarly large fossils can be found in the Selkirk area, as seen in GCA4BZ8, which (unsprisingly) is very close to where these rocks originated from.
Details About this Earthcache
Roadside parking can be found on Miles Avenue. Public Transportation is available on Oxford Street. This park area is available from 8am until 10pm, 7 days per week. However, due to the close proximity to homes in the area, and due to the visual nature of earthcaches, I would ask that you please imit your visit to daylight hours.
This earthcache will not be available when there is excessive snow on the ground. Please be respectful and come back when you are able to fully experience the fossils.
As with all of my ECs, I am not looking for PhD thesis level responses, but I am hoping that you take some time to enjoy the area and learn something new. Please include a list of all cachers with your answer, if answering for more than one caching name.
Logging Tasks:
1. MANDATORY - take a photo of yourself, shoe, hand, thumb, etc pointing at an example of a BODY fossil in the rocks. Attach this photo to your log.
2. MANDATORY - take a photo of yourself, your shoes, hand, thumbs, etc pointing at an example of a FOSSIL IMPRESSION in the rocks. Post this in your log.
3. Using the message feature on geocaching com, send me answers to the following questions:
A. What is the approximate size of the largest body fossil you see amongst the rocks at GZ?
B. What is the approximate size of the largest fossil impression you see amongst the rocks at GZ.
C. Find an example of a trace fossil. Is it bigger or smaller than the body fossils nearby? Does the size of the trace fossil make sense compared to the body and impression fossils?
Other photos are welcome of yourself or your group in the area. Please feel free to log as found as soon as you send your answers and I will contact you if you have any questions. Logs without answers sent may be deleted if answers are not received within 5 days of logging.
This cache was placed by a proud Platinum Earthcache Master.