Searching for the Ordovician-Silurian boundary in Iowa, Midwest, United Stated

[Schroeder88]

I'm wondering if anyone has any knowledge of what I should look for when determining the obvious signs of the O-S boundary. If there is a general strata or formation I should keep my eyes open for when looking for it? I keep seeing a reddish boundary when I search for it online. However, I can't find any pictures from anywhere within 1000 miles of where I am, so am a bit skeptical. Any help would be great! A  clear picture would be better! This image is from Manitoba, Canada. It's description is a bit vague.

[Fossildude19]

Moved to Question and Answers.

 

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Have you read through this article?  LINK

 

Another potentially helpful PDF. LINK