We got a dog at the Humane Society, and the dog was labeled as a lab cross, here is the thing though, she has all the tendencies of a lab, looks like a lab, has a minimual amount of white on her chest, but here is where I don't know on her four paws she has white hair also other than that she is purely black, she will be a year in April and she weighs about 55 pounds. She does one thing that is different though, she will hold a point in addition to retrieving. Could she be a pure bred or cross with a pointer or something.

you look at the dog behind her

Labs don't usually point, she could very well be a pointer/lab mix. As an owner of a mutt, it's sometimes really fun to guess what mix the dog is. I work in an animal hospital and have a great time saying to people "is that a *blankity blank* mix?" just because I've seen so many breeds of dog in the 7 years I've been a tech.Just observe all the breeds you can, sometimes you'll see certain characteristics of other breeds in your dog that you'll recognize. Mutts are the best breed, IMO