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Hello everyone! Now that I've started to split some rocks from my local creeks (Mimico Creek and Etobicoke Creek, Georgian Bay Formation, Upper Ordovician), I'd like some help to identify what I've found. @JUAN EMMANUEL, can you help? Rock #1: This type of bivalve is very common, but I can't decide if it's Ambonychia sp. or Byssonychia sp. The book I have says that they both occur in the Georgian Bay Formation, and they look very similar except Byssonychia sp. "has strong radiating ribs rather than (fine radiating) striae," which is what Ambonychia sp. has. (Hessin, p. 148) What do you think? Rock #2: I've started to find this type of bivalve quite frequently. It looks like the pictures of Cymatonota sp. in the book that I have (Hessin, p. 145), but I'm not sure if this genus exists in the Georgian Bay Formation since Hessin states that "it is moderately common in the Verulam and Coburg formations" (p. 145) but he makes no mention of it occurring in the Georgian Bay Formation. Hessin does state that another similar-looking bivalve can be found in the Georgian Bay Formation: Colpomya sp. (p. 146), so perhaps it could be that? Hessin also discusses a bivalve community that is commonly found in the Georgian Bay Formation that consists of Ambonychia/Byssonychia and Modiolopsis (p. 52), so could this be Modiolopsis sp. instead? As you'll see in Rock #3, the bivalves in Rock #1 and Rock #2 are often found together. Rock #3: "front" - bivalve community, but which genera? Rock #3: "back" - bivalve community (which genera?) along with a couple of brachiopods (I think). It may be a bit too difficult to identify the brachiopods, but I'm hoping that someone out there might be able to - perhaps Onniella sp. or Strophomena sp. for the one on top (positive and negative)? Rock #4: positive and negative of a brachiopod - again, it may be too faint to identify but I'll keep my fingers crossed that someone can help me. Maybe Dalmanella sp. or Paucicrura sp. or Resserella sp.? Thanks everyone! Monica