Review of Recent Geological Literature. 57 
They conclude (I) that the actions of gaseous and aqueous hydro- 
chloric acids differ widely ; (2) that in this group of minerals the gas- 
eous acid attacks apparently only that part of the magnesium which is 
present as the univalent groups — Mg — OH : (.'{) the chlorites are not 
hydrated conditions of the micas, or micas plus water of crystallization. 
Corals and Coral Island*. By James D. Dana. Third edition, pp. 
440; with 16 plates, and many figures in the text. (New York : Dodd, 
Mead & Co., 1890.) Eighteen years have elapsed since the first publica- 
tion of this well known popular work, which is based on observations 
made by the author long before, during the cruise of the Wilkes Explor- 
ing Expedition in the years 1838 to 1842. Changes and additions have 
been made in all parts of the work to bring it up to the present date ; 
and about thirty new pages are inserted, meeting objections to the sub- 
sidence theory of Darwin and Dana. The views of Murray, Guppy, A. 
Agassiz, Semper, and others, accounting for coral islands without subsi- 
dence, are shown to be improbable. "Darwin's theory, therefore, still 
remains as the theory that accounts for the origin of atolls and barrier 
islands, which is not true of any other that has been proposed. Fring- 
ing reefs and isolated coral-reef banks may form in shallow water 
within the growing depths of reef-making corals, and on any kind of 
bottom. But atolls, barrier-reefs, and coral formations of great thick- 
ness require as a rule, the aid of slow subsidence, — as has been true for 
nearly all the thick rock formations over the continents." 
The area of the Pacific ocean-bed which thus appears to have been 
sinking has a length of more than 0,000 miles, with a breadth of over 
2,500 miles, and in its central portion the subsidence is believed to have 
amounted to several thousands of feet. It has been in progress, accord- 
ing to professor Dana, from sometime in the Tertiary era until now, 
probably affecting its maximum area during the glacial period. Correl- 
ative with this downward movement for the tropical Pacific, and per- 
haps for some portions of all theoceanic areas within the tropics, the con- 
tinental lands of North America and northwestern Europe, which were 
glaciated, experienced an upward movement, as the author concludes, 
of similar amount, producing a colder climate and ice-sheets. 
On tin 1 Geology and Physiography of a portion of northwestern <'t>im- 
cdo and adjacent partsof Utah and Wyoming. By Chables A. White. 
pp. 077-71:.': plate Ixxxviii; figures 57-01. (Accompanying the ninth 
annual report of the director of the V. S. Geological Survey.) This 
paper, which relates to the district covered by Powell's Geology of Uie 
I'inta Mov/ntalns (1870), describes the eastern part of the Uinta range, 
< - 1 1 1 by the Horseshoe. Red. and Lodore canons of Green River ; the 
nearly related Yampa plateau and other subordinate folds south and 
Southeast from the east end of the great Uinta anticlinal: the inceptive 
eastward continuation of this anticlinal, to the base of the White River 
plateau, a spur of the Park range of the Rocky mountain system: ami 
the small upthrust Junction and Vampa mountains, which are isolated 
