To Branson- I’m curious about your use of the term “nose auger”. Is that what KeyKeeper posted the links to? Also, are you from Branson, MO? I graduated from Hollister in 1974!
The nose auger (aka shell auger) was the predominant form of augers through the 1700's. There's a fairly good photo at:
http://images.cloud.worthpoint.com/wpimages/images/images1/1/0307/24/1_ffe7bc9de8849f9b4c6c0aa1d697fb0c.jpgI've also attached the photo here.
You can see how it has an "ear" that cuts, and also works to bring up the shavings, as your dirt auger will do. They aren't quite as efficient as twist augers, but I have a couple like the ones in the photo and using them doesn't make me feel like Fred Flintstone. They cut well and they are not slow to cut. The double twist bits we are most familiar with were invented in the late 1700s. The nose auger, and quill and spoon bits were preferred by furniture builders because there was no lead screw to burst out the other side of things like legs when you made the hole deep enough to really hold a tenon.
Keykeeper's links were to other post hole augers, but I think it's pretty clear that these augers were based on the principles of the carpenter's nose auger.
Not from Branson, MO. Branson was my great-grandfather's name. It makes me remember where I came from, and who.