The American Geologist. 
July 190S. 
of these isolated limestone masses, and it is in connection with 
these thai the copper ores aye found. Contact metamorphism 
has not been developed to any great extent in tne limestone 
surrounding the laccolith, but lias been greatly induced in the 
included masses; marble, grossularite, vesuvianite and other 
mineral.- having been produced. Aside from the occurrence of 
the nephelite syenite in the area south of the laccolith, the re- 
gion is interesting on account of the dyke recks which are 
found cutting the andestte of the laccolith. Among these are 
found analcite-tinguaites and camptonites, as well as vogesite 
and diabase. Two main streams now drain the hollow formed 
by the down cutting of the dome where the weaker andesite 
has been laid bare as far as the lime-tone cover has been cut 
back." 
Dr. Finlay's paper was discussed by professor Kemp, who 
called attention to the fact that the character of the intruded 
limestone was not yet entirely clear; and by Dr. H. S. Wash- 
ington, who dwelt on the interest attaching- to the additional 
localities here and elsewhere recently reported for the peculiar 
dyke rocks mentioned. 
The second paper of the evening was by Fred IT. Moffet, 
Columbia University, and was entitled: "'.The Copper Mines 
of Cobre, Santiago de Cuba." 
In this paper Mr. Moffet -aid in abstract: "The copper 
mines of El Cobre are located about nine miles west of the bay 
of Santiago, where a series of eruptive flows, andesites and 
rhyolites, are interbedded with fragrnental rocks, agglomerates, 
breccias and tuffs. The strike of the beds is east and west, and 
they dip at a low angle to the north. The series is cut by trap 
dykes and by two major systems of faults, the older of which 
runs east and west and carries with it the large ore bodies. The 
second major system has direction nearly north and south. 
Cross fault- cut and displace the 'ire bodies of the older system. 
and carry copper, though in less amount. The copper work- 
ings of the old English mining companies produced enormous 
quantities of very rich oxidized ore which gave place in the 
lower levels to sulphides. Much difficult} is encountered in 
handling the mine water on account of the porous nature of the v 
country rock. At the present time the iron ore of the region is 
<>f much greater commercial importance than the copper." 
In the discussion which followed, professor Kemp sp ike of 
tin- great importance to the United State- steel furnaces which 
these deposits possessed on account of their great extent and 
convenient location. The ore is extremely low in phosphorus 
but contain- some sulphur. The copper may again be .of great 
importance though but little is being done at present toward its 
exploration. 
The meeting of the Section adjourned about Q:30. 
f. o. hoyey. Secretary. 
