434 0. G. Rockwood, Jr.—American Earthquakes. 
At many places two or three distinct vibrations were noted, 
and the duration was variously estimated from three to thirty 
seconds. Notes of the direction of vibration are given at 
comparatively few places and present nothing of interest. At 
Columbus, O., chandeliers were observed to sway from north 
to south, the motion continuing for at least two minutes. 
In seeking for a possible connection between this earthquake 
and the geology of the region, we at once meet with a very 
suggestive fact. Crossing the western part of Ohio is an antl- 
clinal. known in the geology of the State as the Cincinnati 
arch.* Its axis or crest is traced from south to north through 
Tennessee and Kentucky, crosses the Ohio River a little east of 
Cincinnati, extends in a direction somewhat east of north, 
passing near and a little east of Belle Fontaine, and reaches the 
lake shore between Toledo and Sandusky, some fifteen oF 
twenty miles east of the former. It probably finds its continu- 
ation in some islands in Lake Erie. Its bearing is nearly par 
allel to that of the folds of the Alleghanies. The rocks 
composing this arch are the Lower Silurian limestones, espe 
cially those known as the Cincinnati group, which occupy 
giving way or snap of the strata forming it, causing 
ng a ne 
fault somewhere near Belle Fontaine. It would be interesting 
recent changes of level in that region, or anything else to in 
cate that the upheaval of this arch may be still in slow 
progress, 
Sept. 21.—Between 22" and 23% light shocks were felt at New 
Tacoma, Washington Ter—JU. S. Weath. Rev. 
Sept. 26.—At 22" 53™ a Jight shock was felt at Fort Yum 
Arizona, duration ten seconds, vibration south to north. An- 
; Se * Geologi Survey of Ohio, vol. i. 
t Geol. Surv. of Ohio, vol. i, pp. 103, 106. 
