:Hmm, this is interesting.  For me, long linear and/or abstract embankments, as well as small dome or round mounds, could be (admittedly stretching the definition a bit) described as stylized symbol effigies, so I don't see the conflict.  However, now I think I understand your perspective.  How shall we resolve this?  I think it is advisable to make it clear that effigy mounds are 1. a type of mound, and 2. generally act as effigies of something, although we may not recognize what that is.   I also think it is desirable to be clear that "mound" has more variability than "effigy mound."  Perhaps we should distinguish between "mound," "effigy mound," and "non-effigy mounds built by the Effigy Mound cultures" or something like that.  Do you have any other ideas?