183 



the continent of South America, from Rosario, on the 

 Parana, to Valparait^o, Chili: — 



Bolax, an umbelliferous plant, above the snow on mountains, 

 collected 10,000 feet above level of sea. Capsicum, Red Pep- 

 per (aji,) very common in the northern parts of the Republic. 

 Prosopis Algaroba, White Algaroba, order Leguminosa3 ; also 

 Black Algaroba is very common. Portulaca ; Verbena, several 

 varieties ; Loasa, Tropceolum, Alstrcemeria, Chenopodium, ScM- 

 zanthus pimiatus, Geranium, Lathyrus puhescens, Argemone Mex- 

 icana, CEnothera, Liqypia, Acicarpha, QninchamaUum, Salpiglossis ; 

 valleys and base of the Andes. Maloastrum, Supinus ; deserts 

 at the eastern foot of the Andes. Medicago sativa, Alfafa, culti- 

 vated for cattle ; M. maculata, weed refused by cattle, the common 

 Aveed of clover fields. Scirpus, Solanum ; Lagoon near San Juan, 

 on the desert. Tessaria ahsinthoides ; border of lagoon, San 

 Juan, Argentine. Republic, October. Stromhocarpa strombulifera, 

 Screw plant ; Traversia, San Luis to the Andes. Larrea divari- 

 cata ; common; Traversia between Mendoza, and San Juan. 



Dr. C. T.Jackson gave an account of the Copper Mine, 

 so called, at Elk Run, Fauquier County, Virginia. 



The copper is found in strata of the Triassic Age, in trap- 

 dykes coming through Sandstone, containing a little of the yellow 

 and gray sulphuret, and the carbonate of copper, azurite, chryso- 

 colla, and malachite in thin films. Had quartz or cai'bonate of lime 

 been the gangue-stone, he should have supjjosed the locality to 

 have been of some economic value. He advised the company not 

 to work it, and afterwards learned that an old mine, in which a 

 shaft had been sunk 150 feet, situated near that place, had been 

 abandoned many years before as unprofitable. 



Dr. Jackson made some further remarks in illustration of the 

 view that the rock, through which the trap-dyke comes, exerts an 

 influence upon its metallic contents, and refei-red to a previous 

 communication to the Society upon this subject. (vSee report of 

 the Excursion Meeting, printed Proceedings, Vol. VI. p. 24.) 



Prof. H. D. Rogers said that Geology was in a state of 



