I was dismayed to discover my intestinal problems were still with me in the morning. Today is Bolivia 's Independence day so most shops were closed. Most of our group went out to watch the big parade but I stayed at the hotel to catch up on my journaling. A little after noon, Mike, Charlie, and I went around the corner for a sandwich. To our surprise, we saw Adam, Annika, and Renna. It turns out that Todd had invited them to come along on our afternoon excursion to the Lomas de Arena dune field south of town.

The bus left for the dunes at 2:00. It is a one-hour drive. Some students decided to sleep in the hotel instead. The dunes are about 30m high. The sand was probably derived from rivers that were much larger in the Pleistocene. North and south winds picked up the sand but then converge at the bend in the Andes and drop their load.

We climbed to the top of a large parabolic dune. A southern air-mass had come through last night and cooled the temperature down to very pleasant conditions. The wind sent sand scurrying from south to north across the dunes. The students played like kids in a big sandbox. I gave a brief summary of sand and sand dunes. Strom impressed me by recognizing that the dune we were on was parabolic. From the top we could see the easternmost range of the Sierras Subandinas, just to our west.

After an hour or so, we headed back to town. At 7:00 we took cabs over to the same area we ate last night. Some of us went to the Guadalajara Mexican restaurant and had a good dinner. Afterward, I returned to the hotel and went to an internet café. There was a nice note from Joan and a couple of other bits of news. After a half an hour I quit and returned to the hotel I was actually in bed by 11:00.