Review of Recent Geological Literature.' 199 
distinction, at least not under the name Huronian, which in the area of 
its original description embraced only one part of the series. 
Prof. N. H. Winchell makes a timely recommendation, on which it 
may be hoped that the state legislature will take prompt and efficient 
action, for the setting apart of some considerable tract of the unoccupied 
lands in northern Minnesota as a state park. The region about lake 
Itasca, which is suggested, possesses not only rare natural beauty and 
diversity with its high morainic hills, majestic pine woods, and spark- 
ling streams and lakes, but also much historic interest from the succes- 
sive expeditions to reach and explore the sources of the Mississippi. 
The later part of this report is by Prof. Alexander Winchell, reviewing 
"American opinion on the older rocks," that is, below the Silurian 
system, with quotations from the principal geologists of this country 
who have given especial attention to these rocks, as Ebenezer Emmons, 
Douglass Houghton, E. and C. H. Hitchcock, Henry D. Rogers, Hall, 
Logan, Whitney, Hunt, Irving, Lawson, and many others. This sum- 
mary is given as the introduction to 'a full discussion of the Taconic and 
ArcliEean systems in the Northwest, which Dr. Winchell hopes soon to 
publish, based upon his own observations and studies. 
The Charleston Earthquake of August 31, 1886. By Capt. Clarence 
Edward Dutton, U. S. Ordnance Corps, pp. 203-528 ; plates vii-xxxi ; 
figures 1-41. (Accompanying the ninth annual report of the director of 
the U. S. Geological Survey.) The first chapter of this very thorough 
and elaborate memoir gives accounts of the earthquake as written by 
persons who experienced it in Charleston. Not a building in the city 
escaped injury, but only few were completely demolished and levelled to 
the ground. Many illustrations from photographs show the damage 
done to buildings of different kinds in Charleston, Summerville, and 
other places, including the ancient churches of St. Michael and St. 
Philip, Hibernian Hall, the Roper and City Hospitals, and brick and 
wooden dwellings. 
Two epicentral tracts are recognized, the principal one about sixteen 
miles northwest of Charleston and six miles southeast of Summerville, 
around which the isoseismal curves are nearly circular, and a subordi- 
nate one about thirteen miles west of Charleston, surrounded by elliptic 
isoseismals with their major axes trending toward the northern or Wood- 
stock epicentrum. The violent upward shocks near these places had 
the effect to drive into the ground the bases of piers on which houses 
are built. Other remarkable effects were the formation of assures ami 
craterlets, the latter being large holes in the sandy and clayey ground 
of the district, from which water poured up, sometimes in jets to the 
night Of several feet. Railroad tracks were displaced and bent, ami at 
a bridge it was seen that the opposite banks of the Ashley river were 
thrown slightly nearer together. 
Captain Dutton computes the depth of the principal or Woodstock 
focus of theearthquake energy to be about twelve miles, with a probable 
