April 20, 1900.] 



SCIENCE. 



615 



season, the traveler is unpleasantly made 

 acquainted with the fact that the whole 

 surface is cut up by a system of shallow 

 gulleys or gutters, in which water com- 

 monly stands, but there is rarely observed 

 a flowing stream. This system of gulleys 

 is not of the familiar dendritic type of other 

 regions. The gutters are all connected, 

 but branch and inter-branch in a very con- 

 fusing manner. There seem to be no trunk 

 streams (properly so called) and tributaries. 

 In fact, there is a perfect net-work or 

 labyrinth of gutters carved into the sur- 

 face of the plain, completely surrounding 

 and isolating low, gently rounded mounds 

 of gravelly material from 30 to 150 feet in 

 diameter, and whose tips represent the 

 original plain surface of the valley floor, 

 and give these ' deserts ' their apparent 

 evenness as seen from a distance. 



The gutters are from 3 to 30 feet in width, 

 and are constantly narrowing and widening 

 from no cause which has yet appeared. 

 Sometimes they head in a small rounded 

 basin, 30 to 50 feet in diameter. Indeed, it 

 may be said that the whole system is made 

 up of rounded, elongated basins, connected 

 by narrower channels. Yet ivhatever may 

 be the iddth, all portions of these gulleys are 

 trenched to about the same depth beneath the 

 original surface, namely, about S feet. The 

 little basins at the heads are as deep as the 

 gulleys on the borders of the 'deserts' where 

 they are about to enter the canon valleys 

 of the main streams. They are floored 

 with rounded, waterworn cobbles of black 

 volcanic rock, of comparatively uniform 

 size, and never seem to contain any ordin- 

 ary stream deposits such as gravel or sand. 



The settlers of the region commonly refer 

 to these depressions, containing standing 

 water during the rainy season, as 'pot- 

 holes,' but it is obvious that they do not 

 represent the typical remolinos or pot-holes 

 of stream-bed erosion. I have the follow- 

 ing explanation to offer : The surface for- 



mation of these ' desert ' tracts is a bed of 

 obscurely stratified, water-laid gravel and 

 sand, containing a scattering of waterworn 

 cobbles. The material has come largely out 

 of the Cascade Mountains, as is indicated 

 by the large numbers of fragments of chal- 

 cedony, agate and opal scattered over the 

 ' deserts.' It was spread far and wide across 

 the valley floor by the Rogue river and 

 tributaries, perhaps during a short period 

 of slight depression, and probably is the 

 equivalent in taxonomic position of the 

 Eed Blufi" gravels of the Sacramento Valley 

 (of about the age, it seems to me, of the II- 

 linoian drift-sheet of the Mississippi Basin) . 

 The canon valleys have been carved since, 

 trenching this gravel formation and cutting 

 into the harder Tertiary rocks below. They 

 reveal to us the fact that the gravel is only a 

 thin layer, usually not much exceeding three 

 or four feet in thickness, spread over the bev- 

 eled edges of the older formations, which 

 were base-leveled to form the general even 

 floor of the valley. 



During ordinary seasons, the erosion of 

 the gulleys proceeds very slowly or not at 

 all, but I learn from the inhabitants that at 

 certain times, not often occurring, after very 

 heavy rain storms, there is a decided move- 

 ment of the water in the gutters, and at 

 such times, the finer material of the gravel 

 formation may be removed and carried into 

 the canons, while the cobbles remain be- 

 hind to encumber the flat floors of the de- 

 pressions. This erosive action is only active 

 as far down as the base of the gravel, where 

 the much harder volcanic rock is encoun- 

 tered, and this may account for the remark- 

 ably uniform depth of the gulleys. Their 

 varying width and the labyrinthine charac- 

 ter of the system maybe due to some struc- 

 tural feature of the gravel formation, not ap- 

 pearing upon a casual examination. 



Oscar H. Heeshey. 



Beagdon, Calif., 

 Feb. 5, 1900. 



