Geology Of The Iron-Ore Deposits Of The Firmeza District, 0riente Province, Cuba

THE CHAIRMAN (WILLIAM KELLY, Vulcan, Mich.).-Some 8 or 9 years ago I was at Daiquiri, only a. few miles east of Firmeza, where there are deposits of iron ore of the same general character. There is a great conical hill, perhaps 800 or 1,000 ft. in height and the ore deposit appears to be somewhat in a canoe shape on one side of the hill. The mining has been done by quarrying the ore in benches. These are called levels and to go to the 10th level it was necessary to take mules and ride to the top of the hill, which was to me an upside down arrangement of numbering levels and a novel method of entering and viewing a mine. A little copper ore can be seen in places, and not being a geologist I thought the deposit might possibly be a gossan, but none of the geologists who have written on the subject approve of this hypothesis and the great question seems to be what part, if any, the limestones have played in the origin of ore; whether these deposits are replacements of limestone and whether they are contact ,deposits between the limestone and the other rocks. Examinations have been made by many eminent geologists and the problem has been discussed vigorously on both sides. The deposits are exceedingly interesting from a commercial standpoint and although they have been studied for a number off years the origin of the ore is still a difficult and somewhat controversial question. J. T. SINGEWALD, JR., Baltimore, Md.-I have had the privilege of visiting these deposits and have been very much interested in this paper, of Dr. Roesler's; having been on the ground, I can easily appreciate the difficulties under which he labored in attempting to work out the geology of that region, and he certainly deserves considerable credit for the way in which he has deciphered the geological relations of the Firmeza district. There are several points in his paper 1 ,would like to discuss; first, in regard to the geological interpretations. His differs from previous interpretations in the relative age of the diorite and the granite, but you will note that Prof. Lindgren suggests the probability. that those two rocks are very closely of the same age, and Prof. Kemp actually suggests, although he does not-accept the idea, that the granite is probably later than the diorite, so that there seems to be no particular reason