While sitting at twilight on the piazza of the rude little inn where we passed the night in this basin, there came out from the edge of the wood on to a broad green plateau a couple of long tailed mountain lions. They were not quite full grown, and were of a tawny color. These creatures, savage and dangerous enough under some circumstances, seemed half tame and entirely fearless, playfully romping with each other, and exhibiting catlike agility. The proprietor of the inn told us that not long since, upon a dark night, they came to the house and attacked his favorite dog, killing and eating him, leaving only the bones to explain his disappearance in the morning. They, too, must have read the regulations, “No firearms permitted in the Park.” The Midway Geyser Basin is situated a few miles directly south of that just spoken of, and contains an extraordinary group of hot springs, among which is the marvelous Excelsior Geyser, largest in the known world. It bursts forth from a pit two hundred and fifty feet in diameter, worn in the solid rock, and which is at all times nearly full of boiling water, above which there is constantly floating a dense column of steam, which rising slowly is borne away and absorbed by the atmosphere. The water which flows so continuously over the brim has formed a series of terraces beaming with beautiful tints. This stupendous fountain is intermittent, giving an exhibition of its startling powers at very irregular periods, when it is said to send up a column of water sixty feet in diameter to a height of from fifty to one hundred feet! So great is the sudden flood thus produced in the Firehole River, which is here between seventy-five and a hundred yards broad, that it is turned for the time being into a furious torrent of steaming, half-boiling water. The Excelsior has also a disagreeable and dangerous habit of throwing up hundred-pound stones and metallic débris with this great volume of water, while the surrounding earth vibrates in sympathy with the hidden power which operates so mysteriously. Visitors naturally hasten to a safe distance during these moments of extraordinary activity.