Ok followed the instructions here http://www.foodnetwork.com/recipes/saras-secrets/buche-de-noel-recipe/index.html

I used the off set spatula to spread the batter in the pan. Then I had a little left on the rubber spatula so I scraped it off and spread. I think that cost me the cake!
It seems the section I did that to came out really flat and crunchy. Any thoughts? I have never made this type of cake before. My son and I dug into the fluffy foamy scraps and boy was it tasty!

sounds like you may have over-baked your cake. genoise is very delicate...especially if you baked it in a sheet pan. next time try a recipe that is in a regular round pan. be sure to not open the oven while its baking. it will fall!!