698 



SCIENCE. 



[N. S. Vol. XXIII. No. 592. 



whicli strike in a northeasterly direction, con- 

 tain a deposit of chalcopyrite, zinc blende and 

 pyrite whicli has been worked intermittently 

 since 1885. The workings consist of a shaft 

 250 feet deep, together with drifts and cross- 

 cuts extending for a short distance along the 

 deposit. The ore minerals are directly im- 

 bedded in the amphibolite and the gangue 

 minerals consist of biotite, amphibole, tour- 

 maline and quartz. Interest centers in the 

 age of the deposit, which is clearly and un- 

 mistakably older than the Carboniferous beds 

 which cover the decomposed and oxidized 

 croppings of the ores. Unquestionably it is 

 also pre-Cambrian, for Cambrian strata are 

 present in both southern Colorado and south- 

 ern New Mexico. Their absence in this par- 

 ticular region indicates simply that this 

 vicinity constituted a land area during the 

 earliest Paleozoic times. 



Examination of other points in the ranges 

 north of Santa Fe by the author and Mr. L. 

 C. Graton, revealed the fact that at a great 

 many other points pre-Cambrian deposits also 

 exist, although in few cases was it possible 

 to prove it so conclusively as was the case at 

 the Hamilton mine. Details of these occur- 

 rences will be described in a forthcoming 

 reconnaissance report of the mineral deposits 

 of New Mexico. In general, there are two 

 tjrpes of deposits, both of which most fre- 

 quently contain chalcopyrite. The first con- 

 sists of stringers and irregular lenses of quartz 

 and calcite enclosing copper ores; the second 

 forms disseminated ores or ' f ahlbands ' in 

 schists, either amphibolites or gneisses. 



It has been known for a long time that the 

 gold deposits in the southern Appalachian 

 states are of early Paleozoic or pre-Cambrian 

 age. The pre-Cambrian age of the Home- 

 stake mine in South Dakota has also been 

 firmly established. The author indicated some 

 years ago the probability of pre-Cambrian de- 

 posits occurring in Wyoming, and recently 

 Dr. A. C. Spencer has shown that the copper 

 deposits of Grand Encampment, in the same 

 state, most likely also belong to the same early 

 period. This leads to the inference that pre- 



Cambrian deposits must be present in Colo- 

 rado. 



The pre-Cambrian deposits, as stated above, 

 are apt to contain copper as the most valuable 

 metal. Their tenor in gold and silver is usu- 

 ally low. Arthue C. Spencer, 



Secreta/ry. 



THE TOEREY BOTANICAL CLUB. 



The meeting of November 29, 1905, was 

 held at the New York Botanical Garden, with 

 Vice-president Underwood in the chair. 

 Twenty persons were present. 



Dr. D. S. Martin exhibited specimens of 

 glassy cinders formed by the burning of masses 

 of rice-hulls near Charleston, S. C, illustra- 

 ting in a striking manner the presence of 

 silica in these hulls. 



The announced paper of the afternoon was 

 by Dr. N. L. Britton, under the title of ' The 

 North American Cactacese.' The speaker re- 

 marked that the Cactaceee of North America 

 were being carefully studied by himself in 

 cooperation with Dr. J. N. Rose, of Washing- 

 ton, in anticipation of preparing a systematic 

 account of this group for the ' North Ameri- 

 can Elora.' The Mexican forms have been ex- 

 tensively collected by Dr. Rose and are being 

 kept under cultivation in Washington and 

 New York. Numerous species from Arizona, 

 New Mexico, Lower California and the West 

 Indies have been secured by expeditions sent 

 out by the New York Botanical Garden and 

 now are under cultivation in New York. 

 Herbarium material is, as a rule, peculiarly 

 inadequate to a proper appreciation of the 

 relationships of the members of this family 

 . and it is hoped soon to have all of the North 

 American species under observation in the 

 living state. Herbarium specimens are being 

 supplemented by photographs and by material 

 preserved in fluids. 



The most recent of the more important 

 papers on the classification of the Cactacese is 

 one by Berger, entitled ' A Systematic Re- 

 vision of the Genus Cereus Mill.' and pub- 

 lished in the Sixteenth Report of the Mis- 

 souri Botanical Garden (1905). This paper 

 has been based chiefly on the studies made in 



