Sedimentary
In Southern Ontario Sedimentary Rock Rules
The bedrock in southern Ontario was formed by a large sea depositing lots of sediment and remains of ocean life. Limestone, Chert, Dolostone, Shale and Sandstone are common to find here. Sedimentary rock is the only rock type that contains fossils! To learn more about fossils click on the button below.
Sedimentary Rock Type Menu
Sandstones
Layered Sandstone
Sometimes you can see sandstone layers deposited at different times. Sand usually indicates water moving through ocean currents, rivers or wave action.
A tour through time
Depending on what minerals are in the sandstone, different colours may result. The red in these samples come from the mineral iron, which gives them the rust red colour. Most are from the Grand Canyon area but one is from PEI's north shore. Which one do you think has been weathered by the ocean in PEI?
Preserving life
Sandstone can also capture and preserve fossils such as this Mosasaur tooth.
Limestone and Dolostone
Limestone
Limestone is a common rock in southern Ontario. It can sometimes contain fossils. It was formed from a shallow sea over this area millions of years ago where sediments settled here.
Fossils in Limestone
Fossils can be found in Limestone and Dolostone preserving life that fell to the bottom of the sea many years ago.
Dolostone
Dolostone does not contain as much Calcite as Limestone. It can still contain fossils, and was formed at the bottom of the sea.
Chert and Shale
Chert
Chert is a smooth sedimentary rock that went through a chemical process. It has very fine grains and as you can see above can make some very sharp objects such as arrowheads or knives.
Shale
Shale is a very crumbly rock made out of fine grained silt and clay, making this a mudstone. It can come in many different colours.
Fossils in Shale
Shale can also contain fossils. The grey rocks with Ammonite imprints are made from Shale. They are very delicate compared to limestone fossils.
