Amcrica?i Association Meeting. 261 
estimate of the rate of disintegration for the 70 feet of Niagara shales 
supporting the Niagara limestone would be one inch a year, with a 
probable rate of two inches a year. But at the lowest estimate no 
more than 12,000 years would be required for the enlargement of the 
upper part of the mouth of the gorge 1,000 feet on each side, which 
is very largely in excess of the actual amount of enlargement. Some 
of the recent estimates, therefore, which would make the gorge from 
30,000 to 40,000 years old, are evidently extravagant, and must in- 
corporate some error in their premises. The age of the gorge cannot 
be much more than 10,000 years, and probably cojisiderably less. 
16. A Recently Discovered Cave of Celestite Crystals at Put-in- 
Bay, Ohio. By Prof. G. Frederick Wright. The principal lo- 
cality in America from which museums have been supplied with speci- 
mens of celestite (sulphate of strontium) is Strontian island, two or 
three miles from Put-in-Bay island, in the western end of lake Erie. 
Just as this supply was becoming exhausted, a remarkable fissure was 
discovered last winter on Put-in-Bay island which is completely sur- 
rounded with very large crystals of this beautiful mineral. The fis- 
sure was penetrated in digging a well seventeen feet below the sur- 
face, and is large enough to permit the entrance of ten or twelve 
people at a time. It is not an ordinary cavern, but apparently is the 
interior of an immense '"geode" lined with celestite crystals. The 
geological formation in which it occurs in the Waterlimeof the Lower 
Helderberg. Large deposits of gypsum occur in the vicinity. 
17. Geography and Resources of the Siberian Island of Sakhalin. 
By Prof. Benjamin Howard, London, England. Sakhalin has a 
length of about 670 miles and a breadth of from 20 to 150 miles. The 
features which the author observed during his visits to the island in 
1890 and 1896, as described in this address, are (i) the absence of 
natural harbors and reliable anchorages around its entire 1,500 miles 
of coast, and the reasons for it; (2) the contrast which this island, 
having no volcanoes, exhibits as compared with the volcanic chain 
of the whole Japanese group and its continuation in the volcanoes of 
Kamtchatka; (3) the contradiction which Sakhalin, possessing an al- 
most subarctic climate, affords to the popular belief that latitude is 
the dominant factor in the determination of climates; (4) its mineral 
resources, especially cOal and iron; (5) the immensity and density of 
the fish shoals in the neighboring waters; (6) the absence of navigable 
rivers; (7) the persistence of unadulterated life and manners in the 
aboriginal Ainos there, as when described nearly three thousand years 
ago by the oldest Japanese historian; (8) the vast numbers of 
medusse (jelly-fish) along the southern coast, and the marvelous 
phosphorescence of the sea as observed by the author; (9) the strate- 
gic value of the island to Russia; (10) the completeness of its adapta- 
tion to its present use as a penal stronghold; (11) the present de- 
velopment of its agricultural and mineral resources, and its pros- 
pective self-maintenance chiefly from its future fishing industries; and 
