Mayhew 1961 June 14 Journal 38. Northern Sonora, Mexico still are not sure of this vehicle's ability in sand, & since it was an awfully long ways to help, we decided we wouldn't try to go any further. We let air out of the tires down to 22 pounds in each rear tire) and churned our way back to the highway. Then we continued east through more of the Golden Desierto. That part of it certainly looks dry now and gives the appearance of being quite dry most of the time. The Larrea divaricata is small, widely spaced, and lacks many leaves. A few animals were seen and a few tracks when we stopped to look, but they were not at all numerous. We caught 3 Callisaurus draconoides, 2 Crotalus graciosa at one of the stops (26 mi. east of San Luis). We passed on building that was a bus stop about 50 miles east of San Luis & one building that was labelled El Puerto 66 miles east of San Luis. These were the only buildings we saw between San Luis & our turn-around 17 miles east of San Luis. At that point we decided to drive out to some dunes about 1/2 mile off the highway.