A brochure guide to the collection should be available on site, but I've included it as an image file in case there are none available. Look at the bottom of the cache description for the link.... Each rock also has a QR code which you can scan on site which will link you to the Park's website.
The local geology is dominated by sedimentary rocks, limestone, dolostone and sandstone, formed by the accumulation of sediments in a marine environment. In our case these were formed during the Ordovician Period, beginning 488 million years ago and ending 443 million years ago. The earth was mostly shallow seas teeming with early life and materials settling on the sea bottom formed the sedimentary rocks you will find displayed in the Park.
There are three types of sedimentary rocks:
Clastic sedimentary rocks are formed from the debris of mechanical weathering, like sand and rocks, compressed over time into solid stone.
Organic sedimentary rocks form from the accumulation of plant and animal debris, mostly the calcium that makes up the shells of zooplankton, shells, and corals.
Chemical sedimentary rocks form when dissolved minerals precipitate from solution, falling like a fine dust onto the bottom.
You will also find much older rocks in the Park, dating from the Precambrian age, older than 600 million years. These are not sedimentary rocks but rather igneous and metamorphic rocks which were not formed locally. These rocks were collected locally but arrived due to glacial action.
You will find an explanatory brochure at the little kiosk that will give you some information on the exhibits, and I've included it in the photo gallery in case they are all out. Each exhibit also has a QR code which you can scan with your smartphone for a more detailed look at the geology.
To log a find on this EarthCache answer the following questions as you explore the rock collection.
1. At the mapboard near the trailhead, find the town of Almonte, and identify the type of rock underlying the town.
2. Identify by name and number any three of the five Precambrian rocks in the collection that were deposited by glacial action.
3. Examine the limestone samples #15 & #16; was this limestone formed by organic sedimentation or chemical sedimentation? How can you tell?
4. Optional task: find and photograph an Ordovician fossil, upload it with your log and identify it if you can.
