Wednesday, January 4, 2012

Verulam formation overview

I'm going to have a series of posts coming up that deal with fossils that I've found in the Verulam formation on southern Ontario, Canada. I've trekked up to quarries in the Brechin area a few times in the last couple of years and have only recently sat down to photograph and write about the fossils that I've brought back. My friends Joe and Kevin were the first to introduce me to this formation and the treasures it holds two years ago.

To get started, here is a picture of one of the quarries. All the rocks you see are part of the Veurlam formation

Here is another view from inside the quarry looking back towards where the first picture was taken. The layers of rock are nearly horizontal in their position as there have not been any mountain building orogonies in this part of the North American continent in millions of years.

Collecting is simple enough since most of the quarry is well weathered. The quarry is active and the best stuff is often found in the recently dislodged rock after a blast but there is enough other material around from earlier operations that it is not difficult to locate a nice specimen or two. Like any fossil locality much of what you find are common fossils but there are quite a few different species found here and the more uncommon and rare species seem to be easier to find.

The Verulam formation is upper Ordovician in age (about 450 mya) and is placed within the Katian stage based on the International Commission on Stratigraphy's time scale (Click Here for the chart). To place it within the stratigraphic positions more commonly used in North America, it is equivalent to the Mohawkian stage. In the UK it is equivalent to the lower Caradocian stage that is more commonly used there. As such, the fossils found here are similar to those found in the Ohio/Indiana/Kentucky/Tennessee region of the US but are slightly older since the Cincinnatian stage (local term for the Hirnantian and part of the Katian stages of the upper Ordovician) are 449-440 mya. The Verulam formation is bounded by the Bobcaygeon formation below and the Coburg formation above.

For the next month or so, all the fossils that I will be writing about will be from the Verulam formation. I hope you enjoy reading about them and seeing my pictures as much as I have had finding and researching them.

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