Nice clouds, Steve, but they're not mammatus. Mammatus look more like bunches of grapes hanging off the bottom of large storm cells. I've attached a piccie of mammatus to show you what they look like.
Here's the wiki article on them....
http://en.wikipedia.org/wiki/Mammatus_cloud
I've seen them on a number of occasions up here during the wet season. Can look quite spectacular and rather eerie, especially when they have that iridescent look about them.
The cloud you have (Undulatus asperatus) there looks like a series of waves that have been setup by gravity waves at the base of the cloud. Within the layers you have two or more counter flowing wind currents which generate a set of standing waves as well as microscale turbulent flow. Your clouds are a little more smooth and laminar than the ones in the piccie I've attached.