These were included with a recent acquisition, and I'm curious as to when they might date to.  Any suggestions?  The mail-in card, shown front and back, is mint green, and the Geomorphs flyer (letter-sized page) is actually yellow (lousy scanner app on my phone) with a blank back.

Thanks guys.

Stephen---

The geos ad sheet looks very similar to others I have from a 1 May 1976 TSR distributor "catalog" (a stapled bundle of products listings/ad sheets).  My guess is that the geos ad sheet was done after 1 May 1976, since a) goes don't appear in this set of product listings at all, and b) the footer for most of my sheets has features "Promotional Game Design * Design Consultants" and your sheet doesn't have that.  

I can't help you on the card, although the swooshy arrow does look somewhat familiar.  I'll dig a bit more and see if anything turns up.