558 



SCIENCE. 



[N. S. Vol. I. No. 20. 



hands of the present owner, improvement, 

 cuttings and other topics are discussed. 

 While it was not expected that the forest 

 would be self-supporting fi-om the start, it 

 has been nearly so, the expenditures for the 

 year ending April 30, 1893, being $9,911.76, 

 and the income from sale of ties, cord-wood, 

 lumber and posts, together with the esti- 

 mated value of stock on hand, amounting 

 to $9,519.36. Part of the tract will be man- 

 aged on the regular high forest system Math 

 a 150-year rotation; the rest, on a selection 

 system. Steps have also been taken to re- 

 forest a thousand acres of waste land, using 

 many kinds of native and foreign trees. 

 In connection with this work it is de- 

 signed to build up an arboretum second to 

 none in the world. This is under the di- 

 rection of Mr. Frederick Law Olmsted. 

 Already there are in the nursery more kinds 

 of trees and shrubs than in the gardens at 

 Kew, and the number is being steadilj^ in- 

 creased. This arboretum will form the 

 borders of a drive about five mile long. 

 Careful records are being kept in connection 

 with the work, and a forest botanical librarj^, 

 already of considerable extent, will furnish 

 the necessary aid to study. Accompanying 

 the report is a map of the forest and a num- 

 ber of good half-tones showing original con- 

 dition, proper and improper methods of 

 himbering, etc. This is the first time proper 

 forest management has ever been under- 

 taken in the United States, and as time 

 goes on the results will undoubtedly become 

 an object lesson of prime importance, and 

 one badly needed by the American public, 

 whose delight from the earUest settlement 

 of the country has been to destroy trees. 



E. F. S. 



SOCIETIES AND ACADEMIES. 

 GEOLOGICAL SOCIETY OP WASHINGTON. 



The following are abstracts of the com- 

 munications presented at the 38d meeting, 

 April 24, 1895 : 



W J McGee. ' The topographic devel- 

 opment of Sonora.' 



The territorj' described, Ijing between the~ 

 Gila river on the north and the Eio Sonora 

 on the south, and extending from the Sierra 

 Madre to the Gulf of California, is about 

 400 by 200 miles square. Essentiallj- it 

 consists of an undulating plain with em- 

 bossed mountain ranges. The plain varies 

 from sea-level to some 4000 feet in altitude; 

 the mountain ranges, commonly 4000 feet 

 or less in height above the plain, are rug- 

 ged, narrow and generallj' parallel, trending 

 somewhat east of south. These ranges are 

 remnants of larger mountain areas, shaped 

 by erosion, and sometimes they are con- 

 nected by transverse ridges which, like the 

 ranges themselves, are residua of ancient 

 masses. The area is one of complete grada- 

 tion within itself, i. e., the rainfall is so 

 slight that the material degraded from the 

 mountain is aggregated on the iatermon- 

 tane plains, as the storm-waters sink or 

 evaporate — for none of the rivers between 

 the Gila and Yaqui ever reach the sea. 

 Certain peculiarities of the topography 

 grow out of this condition. 



The entire plain incliues south westward, 

 having evidently been tilted in this direc- 

 tion during late geologic time, though the 

 date is not yet fixed. A consequence of 

 this tilting was the stimulation of the 

 streams flowing westward, southward and 

 southwestward, and partial paralysis of the 

 streams flowing hx the opposite direction ; 

 and by reason of previous adjustments of 

 topographic processes and products under 

 the peculiar cUmatal conditions of the re- 

 gion these effects were greatly increased. 

 Accordingly the southwestward-flowing 

 streams reti-ogressed and pushed their head- 

 waters through the parallel ranges and 

 sometimes through the transverse ranges 

 connecting them, while the northeastward- 

 flowing streams practically ceased to cor- 

 rade. Accordingly the area is characterized 



