Great range composed of boulder clay. Daraily. Lost on the savannahs. Jamaily. A deer-hunter's family. Totagalpa. Walls covered with cement, and whitewashed. Ocotal. The valley of Depilto. Hawks and small birds. Depilto. Silver mine. Geology of the valley. Glacial drift. The glacial period in Central America. Evidence that the ice extended to the tropics. Scarcity of gold in the valley gravels. Difference of the Mollusca on the east and west coast of the Isthmus of Darien. The refuge of the tropical American animals and plants during the glacial period. The lowering of the sea-level. The land shells of the West Indian Islands. The Malay Archipelago. Easter Island. Atlantis. Traditions of the deluge. BIDDING adieu to our hosts, we mounted our mules and descended the ridge on which their hut is built. The range was very steep, and fully 1200 feet high, composed entirely of boulder clay. This clay was of a brown colour, and full of angular and subangular blocks of stone of all sizes up to nine feet in diameter. The hill on the slope that we descended was covered with a forest resembling that around Santo Domingo, though the trees were not so large; but tree-ferns, palms, lianas, and broad-leaved Heliconiae and Melastomae were again abundant. In these forests, I was told, the "Quesal," the royal bird of the Aztecs (Trogon resplendens), is sometimes found. After descending about 1000 feet, we issued from the forest and passed over well-grassed savannahs surrounded by high ranges, on the eastern slopes of which were forests of pine-trees. The ground was entirely composed of boulder clay, and not until we had travelled about five miles did we see any rock in situ. This boulder clay had extended all the way from San Rafael, and ranges of hills appeared to be composed entirely of it. The angular and subangular stones that it contained were an irregular mixture of different varieties of trap, conglomerate, and schistose rocks. In the northern states of America such appearances would be unhesitatingly ascribed to the action of ice, but I was at the time unprepared to believe that the glacial period could have left such a memorial of its existence within the tropics, at no greater elevation above the sea than 3000 feet. Riding on without stopping, we passed through Yales, a small village of scattered huts, and reached a river flowing north through a fine alluvial plain almost uninhabited. After crossing the river three times, we turned off to the north-west, and passed over low grassy ranges with scattered pine-trees, and in the hollows a few clearings for growing maize, wheat, and beans. At noon we halted for an hour to let our mules feed on a small alluvial flat, for they had had nothing to eat the night before on the bleak mountain summit.