VIEWS OF VARIOUS GEOLOGISTS 471 



In presenting the views of others it will be proper to commence with 

 the publications of Professor Dana. 



Views of J. D. Dana 



The lava and tuff cones of Oahu were first described in the Eeport on 

 the geology of the regions examined by the United States exploring ex- 

 pedition. The observations were made in 1840 and the volume was 

 published in 1849. The same description reappeared in "Characteristics 

 of volcanoes,"* with additions. 



Accurate drawings of the craters, Mauumae, Kaimuki, Diamond head, 

 Punchbowl, and the two Koko heads, with descriptions, are presented. 

 Mauumae is said to be a lava flow; Kaimuki is not defined, but all the 

 others, including the three salt lake craters, are spoken of as "tufa cones." 

 Diamond head is said to be a "fine example of the typical tufa cone in 

 its broad and shallow saucer-shaped crater, with the stratification parallel 

 to the bottom of the saucer and to the original outer slope" (page 293). 

 Punchbowl is said to be composed of "a yellow to -brown, in part resin- 

 lustered, palagonite-like rock bearing evidence in its constitution and in 

 the dip of the beds that mud-making, warm waters were concerned in the 

 disposition; and the brown, in place of red, color is probable evidence 

 that the temperature of the water was below 200° Fahrenheit" (page 

 292). He remarks that "Diamond head may have been thrown up in a 

 single year or less" (page 295), and refers to some notable recent erup- 

 tions which had likewise been formed in a very brief time. These were. 

 first, Tarawera, New Zealand, where "the eruption was ended and the 

 clouds of dust gone in six hours" (page 246). Secondly, in 1883 Kra- 

 katoa accomplished its work in thirty-six hours. Thirdly, Baldaisan, in 

 Japan, sent forth steam, dust, and possibly lava, in 1888, the action being 

 of extreme violence. "In one hour the dust shower had mainly passed, 

 and in five hours it had wholly ceased" (page 253). 



Views of W. T. Brigham 



Professor Brigham describes and figures Diamond head and its sur- 

 roundings, f There is a cone of tufa whose layers have dips, probably 

 comparable with the descriptions of Dana, and the laminae are separated 

 by calcareous deposits. They also contain fragments of coral in consid- 

 erable quantities, undecomposed and in masses of from two to twenty 

 cubic inches. The region adjacent is an elevated coral reef. No lavas 



* Dodd and Mead, publishers, 1890. 



t Memoirs Boston Soc. Nat. Hist., vol. i, 18G8. 



