I have two 1960 convention guidebooks with different front and back covers. Can anyone tell me why there were two different covers for this convention? Also, pages 38, 39, and 40 are blank with "NOTES" at the top of these pages in my top photo. The bottom book has photos of formations on pages 38, 39, and 40. One last difference, one has no publisher noted, the other was published by Beedle Publishing Company, Carlsbad, New Mexico.