Geology and Mineralogy. 243 



square inches in area, and up to one-fourth of an inch in thick- 

 ness; the largest single mass weighing, with some of the adherent 

 slate, about 5 lbs. 



The sulphides are not crystallized ; but appear to be almost 

 homogeneous and are comparatively rich in lead and zinc, an 

 average assay yielding 85 per cent of zinc and 20 per cent of 

 lead, with 25 ounces of silver and one-fourth an ounce of gold to 

 the ton. An assay made by Dr. A. R. Ledoux proves the silver 

 to be almost absolutely pure, containing only 1 per cent of native 

 gold. The silver occurs in veins, with more or less open spaces, 

 and showing very minute crystals on the upper and lower part of 

 the vein. A near view, side-ways, reveals it to be in fibrous 

 masses and ropes, having all the appearance of sweating out of 

 the rock, probably a result of the decomposition of the chloride, 

 leaving the silver in fine, fibrous masses, varying from short ropes 

 10 millimeters in diameter to the fineness of a hair. 



The specimens and information were kindly furnished by 

 Wyndham H. Wynne, of Glendalough, Ireland. 



5. On the occurrence of polycrase in Canada ; by G. Chr. 

 Hoffmann. (Communicated.) — Fine examples, of what on ex- 

 amination by Mr. R. A. A. Johnston proved to be polycrase, have 

 been found by Mr. C. W. Willimott, in the township of Calvin, 

 district of Nipissing, in the province of Ontario. It occurs here 

 in the form of crystalline masses — one of which weighed rather 

 more than seven hundred grams — associated with xenotime, a 

 highly altered, cleavable massive form of magnetite, and small 

 quantities of a brownish-red spessartite, in a coarse granite vein, 

 composed of quartz, microcline, albite or oligoclase, muscovite 

 and biotite, which is there found cutting a reddish, fine-grained, 

 hornblendic gneiss. The mineral has a pitch-black colour ; an 

 uneven, in parts subconchoidal fracture ; a resinous lustre ; is 

 brittle; and affords a grayish-brown streak. Its specific gravity, 

 at 15-5° C, is 4-842. A very carefully conducted qualitative 

 analysis showed it to contain — Niobic oxide, large amount ; tan- 

 talic oxide, somewhat small amount; titanic oxide, large amount; 

 yttrium oxide, somewhat small amount ; thorium oxide, small 

 amount; stannic oxide, trace; cerous oxide, small amount; lan- 

 thanum oxide, small amount; didymium oxide, small amount; 

 uranous oxide, small amount ; ferrous oxide, small amount ; mag- 

 nesia, trace ; water, very small amount. Zirconia was sought for, 

 and found to be absent. 



6. The Kaolins and Fire Clays of Europe, and the Clay- 

 working Industry of the United States in 1897; by Heinrich 

 Ries. From the Nineteenth Annual Report of the U. S. Geologi- 

 cal Survey, 1897-1898. — Professor Ries has here brought together 

 a large amount of important information on the occurrence, com- 

 position and general use of the clays from the important localities 

 in Europe. This is chiefly based upon the personal observations 

 of the author during recent visits to the localities themselves. 

 The value of the paper will be appreciated when the importance 



