Leaving Algiers in October, diligence was taken to Ghardaia, the most important town in southern Algeria and the end of the diligence service. Beyond Ghardaia travel is by camel only. The diligence journey, if made without stop, requires six days, running night and day, except the first day’s run, which is by day only. Pauses in the journey to Ghardaia were made at the leading towns or stage stations (bordj), thus affording opportunity to observe several localities in the High Plateau as well as the portion of the desert just south of the Saharan Atlas. Stop-overs were made thus at Medea, Boghari, Djelfa, Laghouat, and Tilrempt. A fortnight was passed at Ghardaia, where the environs of the city were quite thoroughly explored. As there are no roads between Ghardaia and Ouargla, or between Ouargla and Touggourt, it was necessary to organize a small camel-train, engage a cameleer (sokhrar) and servants, and make special arrangements for the trip. Nine days were required for the portion of the journey to Touggourt via Ouargla. At Touggourt diligence was again taken for Biskra, two days’ journey. The return journey to Algiers from Biskra was broken at Batna for the purpose of visiting the fine forest of cedar (_Cedrus atlantica_) in the mountains not far from the town. When Biskra was revisited, in the spring of 1911, the northern portion of Algeria was crossed on the way from Tunis, this affording an opportunity to observe something of the picturesqueness of the mountainous regions as well as the spring flora. I wish to take this early opportunity to acknowledge my appreciation of assistance received from different persons during the course of the Algerian study, or as a means of preparing for it. I am especially indebted to Prof. H. J. Hall, of Leland Stanford University, who was my companion in Algeria and whose knowledge of the American deserts made his advice doubly valuable. Dr. Keltie, secretary of the Royal Geographical Society, provided letters and information of much use. Dr. Trabut, government botanist of Algeria, whose acquaintance with the country is extensive, very kindly identified all plants sent him and gave valuable aid in other ways. The map (plate A) was prepared expressly for this study by Mr. Godfrey Sykes. In a country where travel away from the beaten path is not without discomfort, it is important that the way be made as smooth as possible, not alone for comfort but for personal safety as well, and it is therefore a pleasure to acknowledge the many kindnesses shown by the civil and military authorities of the French colony, as also by the American consul and vice-consul at Algiers. =GEOGRAPHICAL CHARACTERISTICS OF ALGERIA.=