I have yet to see edge marks left on a historic hewn timber which look like it was made by an adz. All of the marks I have looked at have an arc to the swing, as shown by the nicks in the blade, and if the blade did not exit the cut you can see that the cutting edge is rarely perpindicular to direction of the swing. Below is a photo of an ax mark from about 150 years ago which shows what I am saying. http://i121.photobucket.com/albums/o223/jimderby/IMG_3188.jpg
My question is were adzs ever used to dress timbers?
Another photo I will include is one with two axs laid on two collar beams from the same carrage house in the position the marks show that the axs stopped during hewing. (the third beam in the photo is under the handles to keep the axs in position).