this artificial canoeing course north of Ann Arbor, MI has proven to be a great collecting site. the breaker rocks appear to contain abundant stromatolites and ichnofossils, plus a few brachiopods and possibly stromatoporoid breccia and cephalopods. The rocks greatly resemble the Mid Devonian reef limestone further north, but theyre much harder and compacted, plus they bear styolites/shale layers and silica inclusions characteristic of the Detroit River Group. the nearby hillside is a good place to find glacial till fossils too. Breaker Rocks and Embankment 1. 2. Ichnofossils 3. 4.