It is clear now that the rear opening is the orbit ( where the eye goes). It is very smooth inside and of considerable size. The front opening is the naris, which the animal breathed through. The breathing opening is quite large - perhaps the animal had large lungs for deep diving. This might also explain the large eyes. Deep diving requires large eyes to see prey and predators. As I remove excess matrix the skull is getting even more light and fragile, but is very elegant. I understand that this is the first 3D Thalattosaur skull ever found, and one of the very few of any kind from the Triassic.
Last, I don't remember if I've previously posted this. Here is the skull with the large break across the nose corrected . The nose droops even more than at present due to an existing offset. I intend to remove the nose, remove all excess matrix, and repair the nose so it looks like this picture (but with all the excess matrix removed, of course). I'll be away for 3 weeks so the next post will probably be a month off.
By the way, if you are in the Portland Metro area on August 9th check out the NARG group's Fossil Festival at the Rice NW Museum of Rocks and Minerals, It is free, and a lot of fun. Bring the kids!
Sincerely, Greg Carr