312 Scientific Intelligence. 
graptolites; and hence the limestone adjoining them and con- 
formable in be edding with them was reasonably felted to the 
Lower Silurian. He writes that as to tlte precise period of the 
Hoosic slates, then made “Hudson River,” he is at present 
uncertain. 
At the Montreal meeting of the British Association Professor 
Hall expressed his belief in the synelinal character of Mt. Wash- 
ington—the subject of the writer’s paper at page 268 of this 
volume, and in the general synclinal character of Kes bea 
ef 
= 
2. EHarthquakes of Ischia.—The facts connected with the ‘enihe 
quakes of Ischia, from 1828 to 1883, and the theories brought 
forward in explanation, are discussed b r. Francis DuBois, in 
esumé.—W hat then do we really ‘know about the Ischian 
earthquakes ? tA oat is admitted by all or denied by none 
at fh be accepted as true. 
1 Ischian earthquakes: of which ed special record has been 
made resemble each other, in fact are a counterpart of one another, 
differing only in intensity, having a special type of which the 
fo ~ owing are the common and constant characteristics : 
If there are any premonitory signs one never hears of them 
ntl after the eid meng has taken place. There are always 
prophets after an eve 
(2) Great suddenness ; there is but one serious shock and all is 
ti 
intensity of the mic wave as it heey from the seismic center, 
ut the area of pein is clearly ma 
(4) The cause of the earthquake ehelster it may et dean 
it be a fissure, or the formation of a volcanic rent, sub- 
terranean falling in, or explosion, or what not, is compare 
near the surfac 
(5) There a no evident voleanic phenomena ee 
the Broa uake. 
f the ited wave is felt outside of the island at all it i 
felt a sligh 
(7) There i is no disturbance of the sea 
(8) Three days after the earthquake of 1881 there was not the 
least vibration of the soil discernible even with a microphone. 
Strange to say no notice one way or the other hab reached me 
with rerard to the earthquake of 188 
Conclusions.—(1) That it is very much to be regretted that after 
the disaster of 1881 no efficient measures were taken to investigate 
the Fit Aine phenomena of the island of Ischia. 
That it is very difficult to arrive at any positive conclusion 
rom reading the different reports. On doing so, one has 
e 
