•'>8 J III Anirricd II (riolofjlKf. Jiiniiarv. ISlCi 
Tin (riilf (if .}fi riiii IIS n iiiriisiiir iif IsDstasi/. I)}' \V J ^I(( ii:i:. Bulle- 
tin, G. S. A., vol. III. pp. oO]-")0;i. Subsidence of ditterent portions of 
the shores of the ^ulf of ^[exico appears to be closely proportionate 
to the local rates of deposition. It is thus indicated that throughout 
the southeastern part of North America isostasy is probably perfect, 
or, in other words, "that land and sea t)ottom are here in a state of 
hydrostatic equilibrium so delicately adjusted that any transfer of 
load |)roduces a precisely e(|uivalent deformation." 
This paper is published in the .\merican Journal of Science for 
September. 1S!)2. 
Till Ii-ui/iiuis .•-■//.„•, iinrlli 'if till AiliriHiiliirks. By .] . W . Si-kncki;. 
Bulletin, Cf. S. .V.. vol. iii, i)p. 4SS-4l)l. Plains and terraces of gravel 
and sand, occurring on the rivers Howing northward from tha Adiron- 
dacks. mostly between 700 and 1,200 feet above the sea, are regarded 
as evidence of the extension of the Iro(|Uois shore to a distance of 100 
miles northeastward from Watertown. Though this shore is con- 
tinuous from Watertown southward to Uome. 440 feet above the sea, 
at the present divide between lake Ontario and the Mohawk. Prof. 
Spencer believes that the Iro(|uois water body was an arm of the sea, 
and tiiat this region has been differentially nplifteil since the Ice age 
to a maxmium amount of about 1.200 feet. 
('hitiiiiih iii-ir iliriilis iii,t iriilnin- ])er ae of ;/hici(tl liiLis. iiy J. \V. 
Si'KxtKu. Bulletin, G. S. A., vol. in. ]>p. 491, 492. On the western side 
of the Adirondack (/)f^s•.v/;■. the divide between the head of the valley 
of the Black river and that of an eastern branch of the ^Mohawk is 
1.141 feet above the sea. Terraces of sand and gravel lie at a consider- 
able hight above the streams both north and south of this divide, the 
highest on the north, near Boonville. being at 1,190 feet, and the 
highest ten miles south of the divide i)eing at 1.095 feet, which is 325 
feet above the adjacent stream in the bottom of the valley. These 
terraces are regarded by the author as the former shores of a marine 
strait during the subsidence with which the Glacial period ended. 
In the discussion of these papers, Mr. G. K. Gilbert, who had ex- 
amined these areas with Prof. Spencer, attributed the plains and ter- 
races to river action attendant on the recession of the ice-sheet, but 
could not regard them as shore lines either of lakes or of the sea. 
yntis ,,„ tin Cnlni/i/ nf III, Ynhnn l„,sni. I'.y ('. Wll.l.AKl) IIaVICS. 
iUilletin. <i. S. .V.. vol. ni. ])p. 49"), 496. This is a very concise abstract 
of the author's observations in the summer of 1891, during a journey 
of about 1,000 miles through the country east and north of Mt. St. 
Ellas. The interior range of the St. Elias mountains, extending north- 
westward toward ^Lt. Wrangell, is found to have a simple synclinal 
structure and is composed chiefly of Carboniferous and Triassic strata. 
The white volcanic tuff which has been noted by various travelers 
on the i>ewes and Peliv rivers was found to increase trraduallv toward 
