458 



SCIENCE 



[N. S. Vol. XXXVII. No. 951 



on either side of the canyon is directed away from 

 the margin of the walls and not into the great 

 trough. In some eases these reentrants are par- 

 tially accounted for by the presence of faults 

 trending transversely to the course of the river. 

 In the majority of other cases the amphitheaters, 

 great and small, appear to have originated 

 through undercutting by differential wind action, 

 the detlative effects being much more vigorous on 

 the soft shales lying between the hard Carbonic 

 limestones forming the upper wall and the hard 

 granite floor of the inner canyon. 

 Geologic Significance of Enisled Relief: Charles 

 R. Keyes. 



Sharp meeting of lofty mountain and even 

 plain, seemingly as level as the ocean strand-line, 

 is one of the most characteristic features of desert 

 landscapes. Foothills are also conspicuous by 

 their absence. The very deficient rainfall of such 

 regions can not possibly produce such topographic 

 peculiarities. On the Mexican tableland, for in- 

 stance, where the geologic structure presents a 

 great thickness of soft later deposits, and the 

 whole selberglandschaft of the Germans is prob- 

 ably more ideally perfect than anywhere else on 

 the globe. A number of typical illustrations are 

 described. The phenomena are best explained by 

 the action of regional eolation, or general leveling 

 and lowering of the country through detiation. 

 Some Upland Flats in Jo Davies County, Illinois: 

 A. 0. Trowbridge. 



An attempt to distinguish between raised pene- 

 plains, structural plains, plains of marine deposi- 

 tion and plains of marine erosion, in regions of 

 nearly horizontal strata. 



The Value of Geochemistry to Geology and, Geog- 

 raphy: J. Culver Hartzell. 

 The author stated that geology is the history of 

 the earth, including organisms; geography is that 

 part of geology which deals with the surface of 

 the earth, and man in particular, and his relations 

 to topographical, cultural, political and climatic 

 environments. We are apt to forget the relations 

 which the atmosphere, the hydrosphere and litho- 

 sphere bear to each other. Diastrophism, vul- 

 canism and gradation are important; but the geo- 

 chemistry is as important as the mechanics when 

 changes in the equilibrium of chemical systems 

 and their relation to man are considered. Atoms 

 are different manifestations of one primal force. 

 The farther we get away from primal the more 

 distinct chemical and physical seem. There are 

 pure and applied methods of procedure; but the 



pure and applied principles are interdependent in 

 the proper and accurate interpretation of facts. 

 The value of geochemistry lies in the fact that it 

 touches every <llivision of geology in both its philos- 

 ophy and its applicability. We need to get away 

 from a sole contemplation of finished products. 

 All forces are so balanced as to produce systems 

 which are more or less stable; but which may be 

 disturbed in such a way as to produce new systems 

 which may in turn become more or less stable. 

 These disturbances in equilibrium are as vital to 

 the geologist as the system per se. We know a 

 little about the balancing of forces; but the bal- 

 ancings are so multifarious as to be almost over- 

 whelming, and it is only by careful, persistent 

 investigation, interpretation and application of 

 forces and the formulation of laws (perhaps ten- 

 tative) that we can hope to know the genesis of 

 any one system and its possible disturbance, thus 

 accumulating a mass of data relative to many 

 systems the final interpretation of which will make 

 clear many of the heretofore apparently un- 

 solvable problems. Stability, unstability and dis- 

 turbance cross our path and we must determine 

 their relations. The atmosphere, hydrosphere and 

 lithosphere were discussed. The reactions which 

 take place, the manner and time of occurrence, 

 the phenomena and the final results are the prob- 

 lems of the geochemist. The solution of these 

 problems has a direct bearing on topographical, 

 cultural, political and climatic effects as well as 

 on diastrophic, volcanic and gradational effects. 

 They also have a direct bearing on the igneous, 

 metamorphic and unconsolidated portions of the 

 lithosphere as well as on the morphological and 

 mathematical relations of minerals and their chem- 

 ical molecular arrangement, and the conditions of 

 fossilization with reference to the changes in the 

 solid parts of organisms. 



The author is greatly indebted to Dr. Frank 

 Wigglesworth Clarke's "Data of Geochemistry," 

 and to Alfred H. Brooks's presidential address 

 before the Geological Society of Washington, 

 December 13, 1911, for the thoughts here pre- 

 sented. 



Gas and Oil Wells near Oberlin, Ohio: George D. 



Hubbard. 



Exploitation of the Clinton sands of the Clin- 

 ton formation northward from the Bremen field 

 to Lorain County has gone far enough to find 

 several good wells in the vicinity of Oberlin. 

 Mostly gas of good quality; some yield oil too. 

 Gas is found at a depth of about 2,170 feet below 



