152 QUARTERLY JOURNAL. 



great mineral changes, and instanced the upheaving of a mass of 

 trachite from beneath the sea at Oonolaska, where the sea was 

 made warm for three miles around it. Again, at Banda, a large 

 rock of trachite was forced up through the sea gradually, and heat- 

 ed the water for'a great distance, and the rock remained hot for a 

 year afterwards. Also, the similar case at Sabrina, and at Decep' 

 tion Island in the South Shetlands, where there was no eruption 

 a mass rose up in three or four years, and the water was hot for 

 miles around. 



Here Prof. Shepard asked Mr. Dana if in connection with the 

 order of super-position he had ever seen quartz upon datholite 1 

 Mr. Dana said he had seen phrenite upon datholite, but nol 

 quartz ; and also quartz upon zeolite. 



Prof. Shepard fully agreed in the great agency of hot water ir 

 forming amygdyloid minerals in the trapian rocks. 



A very brief paper was then read by Mr. , on the Geo]o< 



gy of the Island of Jamaica, and one by Dr. Hitchcock, on th« 

 polarity of common trap and boulders ; and the meeting adu 

 journed. 



AFTERNOON SESSION. 



A very able paper was read by Mr, Dewey, on the Gypsum oi 

 New-York. ' 



The rest of the afternoon was spent in a desultory but veri 

 interesting manner, by conversations between the members, oil 

 various scientific subjects. 



Mr. Haldeman of Philadelphia introduced a new and importan ^ 

 chromatic wheel, and explained the same. ^' 



It was proposed to appoint committees of members who Yvf "' 

 near the mouths of all large rivers going into the sea, to note tb « 

 amount of sediment annually carried by the rivers into the sea. "I 



It was also proposed to memorialize the Secretary of War t ^' 

 cause general observations to be made on the change of the ley* ^^ 

 of the coast ; also observations on mean tide level. f 



A new form of improved mountain barometer was introduce »i; 

 by Prof. Jackson or Johnson, and proper stress laid on the necej "Sj 

 sity of improving the barometer, on account of its great super: 

 ority in determining the height of mountains. 



The meeting then adjourned, and the members went to Pro 

 Silliman's residence to partake of his hospitality, where they er 

 joyed a most intellectual treat. 



FOURTH DAY. 



After the previous day's minutes had been read and corrected 

 the names of several new members were presented for approval 

 as was the case yesterday. 



k 



