PEALE] UPPER GEYSER BASIN GRAND GROUP. 219 



The basin of the Saw-Mill is shallow, measuring in its outer dimensions 

 43 feet in diameter. Inside of this is a second basin 27^ feet in diameter, 

 covered with pebbles. The outer circle is bordered bj^ spongiform masses. 

 In the center the geyser tube is funnel-shaped, 7 feet in diameter, sloping 

 to a small orifice. In the outer basin or circle there is a small hole or 

 steam vent. In the outer basin the temperature during the quiescence 

 of the geyser was 176° F. During the second eruption, noted on Septem- 

 ber 10, the temperature was 185° F. This was, however, not in the 

 center, as the spurts prevented the obtaining of it at that place. 



No. 22. Tardy Geyser. — This geyser has a circular basin about 18 feet 

 in diameter, much liJie the Saw-Mill, which is only a few feet north of it. 

 In the center is a funnel-shaped orifice 2 by 2 feet, sloping to a hole 6 

 inches in diameter. The temperature while the water was quiet and filled 

 only the basin of the funnel was 103° F. At 11 a. m,, September 10, 

 the basin was full and the steam escaped in bulges about every 2 min- 

 utes, and the water had a temperature of 169° F. It spouted during the 

 first eruption of the Saw-Mill, the action being very similar, but not 

 reaching quite so high an altitude. During the second eruption of 

 the Saw-Mill the Tardy was quiet. Nothing was determined as to its 

 periods or length of action. 



No. 23. Spasmodic Geyser. — This name I have given to a basin with 

 two orifices, that spouts at intervals not determined. When examined, 

 at 10.30 a. m., September 10, the water was low and had a surface tempera- 

 ture of 193°, and a deep temperature (13 feet below the surface) of 194°, 

 and was in active ebullition. At 2 j^, m. the water was 3 feet below top of 

 the basin, and at 3 p. m. it filled it and was spouting vigorously to a 

 height of 3 to 5 feet. The outer basin is 50 feet in length by about 30 

 feet in width over the two inner basins or orifices, which are much smaller 

 and almost circular. 



Nos. 24 and 25. — These are small spouters. In the morning of Sep- 

 tember 10 the water was low and was pulsating; at 2 p. m. they were 

 empty, and at 3 p. m. were full and spouting actively, the jets reaching 

 heights a couple of feet above the craters. 



No. 30. Bulger Geyser. — This is a cone surrounded by beaded geyserite 

 and having an oblong basin, in which the water rises and falls period- 

 ically. At 10.30 a. m. the water was 3 feet below the top and had a tem- 

 perature of 189° F. At 11.52.45' a. m. the steam was escaping and 

 throwing the water in a bulging mass to the height of 5 feet. The 

 springs included in the group are sufficiently described in the table, and 

 I shall not, therefore, repeat the descriptions here. 



Springs Nos. 1-5 form a small cluster, the drainage from which goes 

 into the Fire Hole at the bend just below the limits of the Giantess 

 Group. 



Many of the springs of the group are situated along the edge of the 

 river, and opposite them, at a lower level, are a number of sj^rings that 

 are included with the Castle Group. Springs 31-33 are surrounded with 

 a deposit of gray geyserite. 



The Limekiln Springs are so called from the fancied resemblance of 

 the mound on which they are located to a deserted limekiln. 



OLD FAITHFUL GROUP. 



The first thing likely to attract the attention of the visitor to the Up- 

 per Geyser Basin, especially if he comes from the south, is the Old Faith- 

 ful Geyser. It is near the south end of the valley, on the left side of the 

 river, 700 feet from the river edge, and is surrounded by four cones, 



