Oct. 27 Pitahaya, 40 km. SE Empalme, 100 ft., Sonora. North side of the river. While we found some interesting areas of mesquite forest with exceptionally large trees, these were some distance from the river. Nearer the river were habitations and along it at most points where we saw it there were large fields of carrizo. Scattered here and there were groves of large poplars which apparently were but small remnants of what was probably a fairly luxuriant riparian vegetation. We found no suitable or interesting collecting and camping sites along the river, and Leopold apparently would not consider a dry camp. We returned to Vicam and decided to leave the Rio Yaqui. Mr. Dedrick accompanied us during our travel near Vicam. He is a missionary working with the Yaqui Indians and attempting, with apparent success, to teach them to read and write and to record the language. From Vicam we proceeded north toward Empalme, with the intention of locating a laguna Leopold had seen from the train on our return trip north, and establishing camp near it. It was marked well in the road by a large detour, and we found it without much difficulty. We found a suitable camp site later in the afternoon.