560 



SCIENCE. 



[Vol. II., No. 38. 



Nebraska. — There are thiity-one observers, from 

 whose r^portslt is found that (he teniperalure and 

 rainfall were about normal. The average mean tem- 

 perature was 75°.4; average rainfall, 3.43 inches. 

 The highest of the maximum temperatures was 93°; 

 the lowest of the minimum, 47°. A violent hail- 

 storm occurred on the 8th, at Lincoln; and a wind of 

 forty four miles per hour, from tlie east, was noted 

 at North Platte. 



Ohio. — The barometric pressure was unusually 

 steady, the small range of 0..542 inches being noted. 

 The mean temperature, 0S°.2, is more than four 

 degrees below the average. A minimum of 39° was 

 noted. Rain fell on seven days only. The average 

 rainfall was only l.SS inches, the usual amount being 

 3.47 inches. At Lebanon 4.00 inches fell, and at 

 Granville 0.70 incli. A violent storm of wind and 

 hail visited Wooster and vicinity on the 2Sth. 



Temiessee. —The reports are from thirty-five sta- 

 tions. The highest of the maximum temperatures 

 noted was 94°, and the lowest of the minimum 43°. 

 The ranges of temperature were generally unifdrm 

 throughout the .state; but the precipitation, which 

 ranged from L03 to 6.38 inclies, was quite unevenly 

 distributed. The weather presented no remarkable 

 features. There was a marked absence of high winds 

 or severe electrical disturbances. The crop reports 

 are excellent, but the average condition is a little 

 below that of last year. 



THE GEOGRAPHIC CONTROL OF 

 MARINE SEDIMENTS. 



M. A. RuTOT, conservator in the Eoyal museum of 

 natural history of Belgium, who, in connection with 

 M. E. Vanden Broeck, has been studying the tertiary 

 strata of his country, has lately taken up [Bull. wus. 

 roy. hist. nut. Bclg., ii. ISS3, 41) the fiuitful subject 

 of the immediate dependence of fragmental marine 

 deposits on geographic conditions, such as distance 

 and form of shore-line, depth of water, currents, etc., 

 and the consequent changes in these deposits follow- 

 ing changes in the controlling geographic surround- 

 ings. The matter is properly treated deductively, 

 and so far as concerns vertical oscillations of the 

 earth's crust, which determine advance and retreat of 

 the shore-line, it is examined with much detail. The 

 conclusion is reached, that tlie frequent changes 

 from gravels, through sands to clays, and back again 

 to gravels, that characterize the Belgian tertiaries, 

 can be fully explained by simple, assignable, and slow 

 , geographic causes. We have only to regret, that, in 

 the forty pages devoted to the subject, more room 

 was not found for mention of what others have done 

 in the same direction. The method of investigation 

 may be outlined as follows: — 



There is first given the familiar illustration of the 

 varied deposits forming off shore at any single time, 

 showing that the texture, and, in part, the composi- 

 tion of the deposits, are functions of the distance 

 from the shore-line, as in fig. 1. Now, let a general 

 depression slowly lake place, by which the sea will 

 advance over the land: the. whole set of deposits 



shifts witli the sliore, until sands, and at last clays, 

 are laid down over the first gravels, as in fig. 2. 

 Then, if elevation replace the depression, the set of 

 strata shifts seaward, and the sands, and at last the 

 shore-gravels, lie above tlie clays, as in lig. 3, It is 

 generally noted that the upper gravels are finer than 

 the lower, as the later deposits are made, in part, by 

 woiking over the older during the time of emergence. 



Fig. 1. 



The complete set of deposits formed during such a 

 double oscillation of sea-level is to be considered in 

 two ways, — first, with regard to the vertical sequence 

 of the strata; second, with reg.-ud to their horizontal 

 equivalence. The vertical sequence is seen in fig. 4: 

 it is made up of the gravels and sands of imuiersicn, 

 the central layer of clay, and the sands and gravels 



of emersion, each stratum having its appropriate 

 fossils. Such 'circles of deposition,' enlarged by the 

 addition of a limestone at the time of greatest dis- 

 tance of the old shore-line, occur several times in 

 our Appalachian sections; and tlie recognition of their 

 meaning, especially in Professor Newberry's luminous 

 writings, has thrown much light on the evolution of 

 our country. M. Rutot gives the accompanying figure 

 (5) to illustrate the succession of unequal or incom- 

 plete oscillations: it shows, I., a large and comiilele 



oscillation, partly eroded before IL, a second depres- 

 sion, from which the elevation was incomplete; III., a 

 great depression and complete elevation ; IV., a mod- 

 erate depression and elevation. This complicated 

 succession represents perfectly the Ijpe of the Bel- 

 gian tertiaries; and the deductions from its physical 

 features are fully confirmed by the evidence from its 

 fossils. 



The second consideration, involving the horizontal 

 equivalence of the different strata, is perhaps the 

 most suggestive part of tlie paper. It is of much 

 importance, and is seldom sufficiently treated. It 



