206 PROCEEDINGS OF THE CALIFORNIA 



Our cavalry here had no grain during the entire winter. This Grama, like the 

 other species, grows in bunches several feet apart, and the lower stalks are green 

 during the winter season. 



No. 4. (Sporobolus airoides, Trin.) This grows in the valleys. A great portion 

 of the Gila Valley is covered with it. Animals eat it readily when green; it is 

 however a powerful diuretic. As a winter grass it is of no account. 



Besides these four enumerated grasses, the letter contained three others from 

 the same locality : 



1. Panieum capillare, L. 



2. Tricuspis pulchella, Kunth. 



3. A Poa, much of the habitat of Poa sudetica. Vivid green ; leaves plane, 

 rather large ; spikelets four-flowered, oval ; lower glume one, and the upper three 

 nerved; lower palea distinctly three-nerved, scabrous on the Red nerve. The 

 nerves of the glumes, as well as of the lower palea, are of a vivid green color ; 

 and exceedingly prominent. The whole aspect of the plant sent, would rather 

 suggest that it is not indigenous to that section of the country. 



Regular Meeting, September, 4th, 1865. 

 Mr. Minns in the Chair. 



Eight members present. 



Donations to the Library : A paper on the origin and for- 

 mation of Prairies, by Leo Lesquereux ; Report of the Van- 

 couver Island Exploration, 1S64; Review of American Birds, 

 by Prof. S. F. Baird ; Silliman's Journal for July ; Proceed- 

 ings of the Essex Institute, January, February and March, 

 1865 ; Illustrated Catalogue of the Museum of Comparative 

 Zoology of Cambridge ; The Naturalists' Directory, Part I. 



Dr. Ayres presented the following paper from Prof. W. P. 

 Blake : 



Note on the abundance of Iron Ore in Northern Arizona. 



BY WM. P. BLAKE. 



Io 1863 I observed an iron formation of considerable extent and interest upon 

 and near the William's Fork of the Colorado, near its mouth. The ore is chiefly 

 the micaceous variety of Hematite, or " specular iron," and occurs in thick beds 

 and in thin sheets, in a ferruginous limestone or dolomite, evidently rnetamor- 

 phic, and tilted up at a high angle. 



It forms a belt of peculiar appearance, that may be traced by the eye for miles 

 across the country, in a direction a few degrees south of west. This rock and 



