306 PROCEEDINGS OF THE ACADEMY OF 



toes too are shorter. The lower mandible is yellow along the entire line of the 

 gonys, and laterally for the basal half. The toes, though evidently not black 

 orginally like the tarsi, are yet of a greenish black in the dried specimen, 

 quite distinct from the decide^ yellowish of the other species. 



An examination of the adult will be necessary to show whether this bird is 

 really the thula of Chili or not. It is certainly larger and otherwise different 

 from specimens brought from Chili by Lt. Grilliss. 



36. Aegialitis vociferus, Cassin, 



37. Calidris arenaria, Illiger. 



38. Fulica Americana, Gmelin. 



39. Graculus dilophus? Gray. Immature. 



40. Thalassidroma melania, Bonap. A single specimen of this species was 

 collected by Mr. Xantus. I have seen one other obtained near San Francisco 

 by Mr. Gruber of that city. 



41. Blasipus heermannx, Bonaparte. Young birds only collected. 



42. Brachyrhamphus hypoleucus, Xantus. The occurrence of a species of 

 this genus as a summer visitor to a point so far south as Cape St. Lucas, or at 

 the latitude of less than 23 N. is a fact of much interest, when we remember 

 that the auks have all been considered more or less arctic birds. The affinities 

 of the new species appear to be chiefly with B. marmoratus, although it lacks 

 the white scapulars, has the inside of the wing white, instead of sooty, and 

 much longer tarsi. Its relations to B. brachypterus, hittlitzii and wrangelii of 

 Brandt it is difficult to determine from the short descriptions of that author. 

 It come closest to the description of B. brachypterus, but the tarsus is shorter 

 than the middle toe, not longer. 



MINERALOGICAL NOTES. No. II. 



BY WILLIAM JOHNSON TAYLOR. 



The number of interesting minerals which have been referred to me by gen- 

 tlemen of the Academy, are but partially described in the present paper. Des- 

 criptions and analyses of several minerals of interest, including at least one 

 new species, I have been obliged to defer for a subsequent communication to 

 the Academy. 



Clayite a new mineral. 



This mineral is remarkable as being near galena in form and composition, 

 being a sulphide of lead with about twenty-five per cent, of arsenic, antimony 

 and copper, forming the third of a series of which galena is the first, cuproplum- 

 bite (found in an adjoining State, Chili) is second, and which contains some 

 copper and sulphur, but not any antimony and arsenic. In the cuproplumbite 

 the lead is partially replaced by copper, and in Clayite this also is the case, but 

 a part of the sulphur is also replaced by antimony and arsenic. 



Clayite is remarkable as containing so small a per centage of sulphur be- 

 tween eight and nine per cent. only. It occurs in small monometric crystals, 

 the predominating form of which appears to be a combination of the tetrahe- 

 dron with the dodecahedron ; they occur as a coating on a layer of quartz, 

 about a thirty-second of an inch in thickness, which incrusts the massive por- 

 tion of the mineral. This massive portion of the mineral is filled with minute 

 quartz crystals, which are microscopic, but the presence of this quartz and the 

 existence of minute fissures has permitted the mineral to be somewhat acted 

 upon by the air, and to suffer a probably partial decomposition, as is evinced 



[Nor. 



