Bibliographical Notices. 307 



discredited at all costs, as subversive alike of religion and of morals ; 

 and in accordance with this view he has had recourse to desperate 

 measures, -which are to be deplored — the more so since they are 

 unnecessary, for the truth can hurt neither if they themselves are 

 true. 



We say, without fear of contradiction, that the theory of evolu- 

 tion is unassailable. It is as well founded as the law of gravitation, 

 as irresistible as the proof of the rotundity of the earth — and there 

 are some who doubt this last fact, even in these days ! 



W. P. PXCRAFT. 



Forest Conditions of the San Francisco Mountains Forest Reserve, 

 Arizona. By J. E. Leibeeg, Th. F. Kjxon, and A. Dodwell. 

 \Yith Introduction by E. G. Plttjimee. Series H, no. 7. Pages 

 95, with seven maps and plates. 4to. Government Printing 

 Office, Washington. 1904. 

 Forest Conditions in the BlacTc Mesa Forest Reserve, Arizona. Pre- 

 pared by I'. G. Pltjmmer from Notes by Th. E. Rixon and 

 A. Dodwell. Series H, no. 8. Pages 62, with seven ma2)s and 

 plates. 4to. Government Printiug Office, Washington. 1904. 

 The forest-conditions of definite regions in the United States are 

 especially described and illustrated in several papers (" Series H. 

 Forestry") of the U.S. Geological Survey Annual Reports and in 

 seven separate memoirs (1902-4). The noted details are clearly 

 and fully described, and good plates of maps, plans, views of 

 mountain and prairie, of forests, woods, isolated timber-trees, and 

 " stands " of special trees are abundantly supplied. 



After having defined the limits of the area to be noticed, the 

 authors give an account of its superficial features, its soil, drainage, 

 water-supply, agricultural and mining aspects, if any. The timber 

 is then considered, Ist, as to the kinds of trees (in memoir " H 7 " 

 12 conifers are enumerated and 10 broad-leaved species ; in 

 " H 8," 9 and 6 respectively) ; and, 2nd, the zones they occupy in 

 the area, variable according to height and exposure to favourable 

 conditions or otherwise. Also as to the estimated quantity and 

 commercial value of the timber which the best sorts of the trees may 

 supply, and the quantity of fuel the poor kinds may furnish. 



The description of the several kinds of trees follows, as to their 

 general habit and style of growth, their merchantable condition, and 

 the calculable value of forest-zone and timber-belt for fuel, fencing 

 material, and mill-timber (some is used largely for railways and 

 mines). Some notes are also given about the deciduous or broad- 

 leaved trees and their relative value in different ways. 



Of course, the forests have been destroyed by the axe to a great 

 extent ; but, besides cutting, other agencies of destruction liave 

 been the following : — grazing, mainly flocks of sheep trampling 

 and eating the seedlings, and fire from hunters' and shepherds' 

 camps, railway sparks, and especially lightning. 



At page 17 of " H, no. 7 " it is stated : — " Among the coniferous 

 species the yellow-pine claims first rank, constituting over 99 per 

 cent, of the merchantable timber and about 90 per cent, of the total 



