920 



SCIENCE. 



[N. S. Vol. III. No. 78. 



parent effect had been produced. The box 

 was then closed and the exposure contin- 

 ued for another half hour. A careful ex- 

 amination at the end of this time led to the 

 conclusion that no visible eifect had been 

 produced. It was found impracticable to 

 continue the experiment longer, as the 

 tube in this time had become excessively 

 heated. 



After the experiment was concluded the 

 plants used were proved to be normally 

 sensitive, as an exposure of one hour to 

 diffused daylight, passed through a small 

 horizontal slit, resulted in a noticeable 

 curvature which in four hours had i-eached 

 60° from the vertical. 



As the inductor was excited to its great- 

 est capacity during the experiment, the 

 plant being placed in as close proximity to 

 the light as possible — and as after the ex- 

 periment the plants were found to be nor- 

 mally sensitive, showing noticeable curva- 

 ture on an equal exposure to diffuse white 

 light — the author concludes that the new 

 rays appear to differ fi-om light in that they 

 do not stimulate heliotropic curvature. 



This contribution to our understanding 

 of the action of the X-rays on plants is 

 very interesting, but it is not thoroughly 

 satisfactory. While light induces a notice- 

 able curvature on certain plants in one 

 hour, the X-rays may not be so active. 

 Until it is possible to expose the plant to 

 the action of the X-rays for a longer time 

 we are not justified in concluding that they 

 have no power to induce heliotropic curva- 

 ture. H. J. Webber. 



U. S. Depaetment op Ageicultdee. 



CURRENT NOTES ON PHYSIOGRAPHY. 

 GREAT VALLEY OF CALIFORNIA. 



F. L. Ransome discusses the heavy cover 

 of fiuviatile sediments, at least 2000 or 3000 

 feet thick, that form the floor of the Great 

 Valley of California, in their bearing on the 

 theorjr of isostacj' (Bull. Dept. Geol., Univ. 



Cala., i, 1896, 371). Although chiefly con- 

 cerned with geological problems, the essay 

 gives a good general descrij)tion of this 

 tj'pical fiuviatile plain, dividing it into 

 three sections, two of which are drained by 

 the Sacramento and San Joaquin rivers, 

 while the third sheds its waters into Tulare 

 lake, of intermittent ovei'flow. The great 

 flat fans built forward by the larger streams 

 from the Sierra are recognized as control- 

 liug the unsymmetrical position of the main 

 rivers, The Sacramento and Feather rivers 

 are said to ' pursue a winding course on 

 low ridges ; ' this unsatisfactory and exag- 

 gerative term, ' low ridges,' being quoted 

 from the Marysville folio, U. S. Geol. Atlas, 

 to name the very faintly convex flood 

 plains built by the rivers themselves. The 

 smaller streams from the mountains ''sel- 

 dom reach the Sacramento directly, but are 

 lost in the intricate plexus of sloughs which 

 meander through the tule (reed) lands bor- 

 dering the main river." A similar study 

 of the Po in its relation to the Alps and 

 Apennines would probably bring ont many 

 resemblances between these great fiuviatile 

 depositories of mountain waste. 



NORWEGIAN COAST PLAIN. 



An instructive account, hy Eichter, of his 

 studies last summer concerns the Norwe- 

 gian coast plain (Globus, Ixix., 1S96, 313), 

 on which Eeusch has already given a brief 

 report ( Norg. geol. Undersog., 1894, with 

 map ; Chicago Journ. Geol., ii., 1894, 347). 

 The coast plain, not to be confused with 

 ordinarj' coastal plains of uplifted marine 

 sediments, is wave cut in solid rock with 

 little regard to structure, and is terminated 

 landward by an abrupt ascent to the high- 

 lands. The visible breadth of the plain 

 varies greatly, depending first on its origi- 

 nal exposure to the waves, and hence hav- 

 ing greater expansion on the ocean front 

 and weakening to a mere strandline or 

 disappearing entirely in the fiords ; second. 



