PEALE.] COMPARISON OF GEYSER REGIONS. 371 



in Iceland is less than 500 feet. In New Zealand the elevations are 

 from 1,000 to 1,300 feet, and in the Yellowstone National Park the range 

 is from about 0,000 to 8,000 feet.* 



The plateau upon which the Iceland geyser is situated is surrounded 

 on three sides with glaciers. In New Zealand the atmosphere is humid 

 and comparatively favorable to a growth of vegetation that is not found 

 in either of the other regions. 



The New Zealand springs are usually of greater size than those of 

 eithtr Iceland or the Yellowstone region. There is in neither of the 

 latter a hot lake, like Eotomahaua, which is a mile wide by a mile and a 

 quarter in length, and has an average temperature of 78° F. The pool of 

 Te Tarata measures 80 by GO feet, and the pool of Otakapuarangi is about 

 50 feet in diameter. Although there are a number of cones or chim- 

 neys, the large basins seem to predominate. In the Yellowstone Park 

 the springs are, as a rule, smaller, although the Grand Prismatic Spring 

 in the Egeria, or midway basin, measures 250 by o50 feet, and the hot 

 lake, near the Steudy Geyser, in the Lower Fire Hole Basin, measures 

 750 feet by 1,000 feet. Still, the geysers usually have cones or chimneys, 

 as in the case of the Union, Giant, Bee Hive, and others described in 

 Part I, many of them being shown in the illustrations. 



In Iceland the springs are also comparatively small, and there appear 

 to be no chimney-like forms ; the Great Geyser is situated on a rather 

 gently-sloping mound, and the geysers at Eeikium have no deposits or 

 mounds. This brings me to the next subject, viz, the — 



Comparative age of the three geyser regions. — It is dithcult, and perhaps 

 impossible, to say, with absolute certainty, which of the three regions 

 possesses the gre<itest age. Still, there are a couple of reasons which 

 appear to me to indicate that they stand in relation to each other as 

 follows, beginning with the youngest, viz : 



Iceland. 



New Zealand. 



Yellowstone National Park. 



The first reason I shall give for this opinion is based upon a compari- 

 son of the volcanic condition of the three regions. 



Iceland may be considered as still in a state of volcanic activity, al- 

 though, perhaps, its fires are gradually becoming dormant, it has had 

 eruptions as late as 1860 and 1875. There are twenty volcanoes on the 

 island, and Hecla, which is nearest the geysers of Iceland, being distant 

 only about 40 miles, has had twenty-two eruptions since 1004 or 1005, the 

 date of the earliest record concerning it. 



In New Zealand the volcanoes adjacent to the geyser areas have sunk 

 into the solfataric stage, and the natives have no tradition of any erup- 

 tions, t In the Yellowstone National Park it cannot be positively de- 

 termined where the ancient volcanoes stand. J It would seem, therefore, 

 that Iceland is the youngest, and the Yellowstone Park the oldest, in 

 its geyser development, if we consider the latter coincident with the 

 later stages of volcanic action. 



Secondly, when we compare the deposits of the geysers in the three 

 regions we find that iu the Yellowstone Park there is usually a chimney- 



*The Thibet region has probably an elevation of at least 15,000 feet, and is there- 

 fore tho most elevated geyser region known. 



t According to Dr. Hector the volcanic forces of the north island of New Zealand 

 were active during the last Tertiary period, and are not yet altogether dormant. 



t Mr. James Eccles, in an article in the Quarterly Journal of Geol. Soc. of London, 

 Vol, XXXVII, Aug., \H6\, advances the opiniou that Mount Washburn is an extinct 

 crater, but iu our opinion the evidence is somewhat obscure. 



