Something has been bugging me for quite a while about these bones - the gastralia in particular. We have two main sizes of gastroliths - some are about 1/8 inch diameter, some are about 1/4 inch diameter. A few are larger and smaller - I have one piece, length unknown (as it's not prepared yet) that appears to be about 3/8 inch diameter - if it's a gastralia. The smallest ones are about 1/16 inch in diameter - thickness of a toothpick. Here is a picture of the longest piece of large gastralia I have found, just uncovered today. The gastralia is the vertical bone across the center. It is about 1/4 inch in diameter (6mm), 165 mm long and had a curvature of 11mm. If we make the assumption that this bone is not too greatly distorted, it may reflect the diameter of the belly of the beast. By standard calculations a chord of a circle with these dimensions will have a diameter of about 630 mm, or almost exactly 2 foot across! So these bigger beasties start rivaling existing crocodiles, larger than Komodo dragons. Unfortunately I cannot easily find the typical diameter of today's large reptiles, so I can't draw accurate comparisons.
Sincerely, Greg Carr