One of the more highly speculative of the Bolivian writers, Señor Posnansky, of La Paz, believes that gigantic balsas were used in bringing ten-ton monoliths across the lake to Tiahuanaco. This theory is based on the assumption that Titicaca was once very much higher than it is now, a hypothesis which has not commended itself to modern geologists or geographers. Dr. Isaiah Bowman and Professor Herbert Gregory, who have studied its geology and physiography, have not been able to find any direct evidence of former high levels for Lake Titicaca, or of its having been connected with the ocean. Nevertheless, Señor Posnansky believes that Lake Titicaca was once a salt sea which became separated from the ocean as the Andes rose. The fact that the lake fishes are fresh-water, rather than marine, forms does not bother him. Señor Posnansky pins his faith to a small dried seahorse once given him by a Titicaca fisherman. He seems to forget that dried specimens of marine life, including starfish, are frequently offered for sale in the Andes by the dealers in primitive medicines who may be found in almost every market-place. Probably Señor Posnansky's seahorse was brought from the ocean by some particularly enterprising trader. Although starfish are common enough in the Andes and a seahorse has actually found its resting-place in La Paz, this does not alter the fact that scientific investigators have never found any strictly marine fauna in Lake Titicaca. On the other hand, it has two or three kinds of edible fresh-water fish. One of them belongs to a species found in the Rimac River near Lima. It seems to me entirely possible that the Incas, with their scorn of the difficulties of carrying heavy burdens over seemingly impossible trails, might have deliberately transplanted the desirable fresh-water fishes of the Rimac River to Lake Titicaca. Polo de Ondegardo, who lived in Cuzco in 1560, says that the Incas used to bring fresh fish from the sea by special runners, and that "they have records in their quipus of the fish having been brought from Tumbez, a distance of more than three hundred leagues." The actual transference of water jars containing the fish would have offered no serious obstacle whatever to the Incas, provided the idea happened to appeal to them as desirable. Yet I may be as far wrong as Señor Posnansky! At any rate, the romantic stories of a gigantic inland sea, vastly more extensive than the present lake and actually surrounding the ancient city of Tiahuanaco, must be treated with respectful skepticism.