Question
I've removed about a foot of yellow, gummy clay soil. Am going to till compost into the soil and top with the remainder of the compost. Is this the best way to break up this terrible clay issue?
Thanks.

Answer
Hi Sam, Clay is not terrible, it just needs to be loosened to help plants get established.  I'd mix 1/3 coarse compost (finely ground pine bark, cotton compost, leaves, etc.) with your clay and put it back in the hole.  Do not put layers of unlike material on top.  Layers cause poor root development and are a watering and wintering nightmare.  
Clay can be an issue if you are trying to grow plants that don't like clay or rather slow drainage. In that case, a little clay and mostly compost works well in an elevated bed that drains more quickly.  
Keep this in mind, it doesn't matter what organic matter you mix into the soil, in about 3 years, it will return to clay. The loosened soil and the stuff you add, makes pathways for the roots to get established. Then the microbes and other soil organisms ingest it and it becomes clay again.  Check your pH also and adjust it if necessary to the needs of what you are planting.
Jim