370 EEPOET UNITED STATES GEOLOGICAL SURVEY. 



land is 360 feet, and in the National Park the Excelsior Geyser has 

 spouted to a height of 300 feet. In Kew Zealand 200 feet is the high- 

 est column recorded.* There are many, however, that spout to the 

 height of 100 feet. The bulk of water in the New Zealand geysers is 

 usually much greater, which is probably the reason the columns, during 

 eruption, do not attai i greater heights. The Thibet geysers spout 50 

 feet, a height frequently noted in the regions just described. 



Eesemblances. — One of the first points to attract attention when the 

 three maps already referred to are compared, is the presence in each 

 of lakes. In Iceland there are sis, in ls[ew Zealand fifteen, and in the 

 Yellowstone IlJational Park there are four of considerable size, besides a 

 number of small and comparatively unimportant ones. 



Lake Taupo, in New Zealand, is 25 miles long and 20 miles wide. 

 Yellowstone Lake is 20 miles long by an average width of about 8 miles. 

 In Iceland Hvitarvatn is nearly 10 miles by 18, and Thingvalla-vatn 

 has a length of about 20 miles and a greatest width of 10 or 12 miles. 



In the three regions hot springs seem to be associated with the lakes, 

 and especially is this the case in New Zealand and in the Yellowstone Na- 

 tional Park.t Although we have not considered the Thibet geysers in 

 the comparisons we have made, it is interesting to note that they are 

 found near the the Lake Tengri Nur. 



In Part II, Chapter II (page 313), we noted the fact that the springs 

 of New Zealand could be grouped in three parallel lines, the most eastern 

 of which was the longest. In the Yellowstone National Park there ap- 

 pears to be a similar linear arrangement. The Mammoth Hot Springs, 

 the Gibbon Geyser Basins, the geyser basins of Fire Hole Eiver, and 

 the Shoshone Geyser Basin are on the same north and south line in the 

 western part of the Park. In the east. Brimstone Basin, the Pelican 

 Creek Springs, and the springs of the East Fork appear to indicate a 

 •second line, while between the two are several scattered spring areas. 



The extension of the western line northward and southward beyond 

 the limits of the Park has already been indicated. 



This linear arrangement ai)pears to be analogous to the linear ar- 

 rangement so frequently noted in the case of volcanoes. 



Another i)oint of resemblance between the three regions is in the 

 character of the deposits, which are alike in appearance, structure, and 

 dhemical composition, with the exception of the minor constituents, as 

 ^hown in the chapter giving the analyses. The character of the rocks 

 is also similar, acidic volcanic rocks being predominant in each region. 

 In Iceland rhyolite, phonolite, and palagonite are found in the vicinity 

 of the geysers. 



In New Zealand rhyolites and rhyolitic tuffs are the prevailing rocks. 

 According to Hochstetter, the rocks of Lake Taupo are quartzose tra- 

 chytic lavas. 



A glance at Mr. Holmes' geological map of the Yellowstone National 

 Park will show that rhyolites are the prevailing rocks. Mr. Holmes' 

 report will present more detailed information in regard to them, and to 

 ipt the reader is referred. New Zealand and Iceland are alike in being 

 islands. 



Differences. — In elevation above sea-level we find that the three re- 

 gions under consideration are very different. The geyser of Haukadal 



*J. G. Corbett in Traus. New Zealand Institute. 



t The geological map of Mr. Holmes indicates that there were formerly lakes of 

 greater extent than exist at present, and that the geyser basins of Fire Hole Eiver, 

 OT ait least the lower one, are the sites of ancient lakes. 



