GEOLOGY. 289 



and many important facts concerning that singular and interesting region are 

 given. 



CHRONOLOGY OF THE FOiniATIOXS OF THE MOON. 



Professor Niehol at the British Association stated that to our satellite 

 hitherto those very ideas have been applied which confused the whole early 

 epochs of our terrestrial geology, the notion, viz., that its surface is a chaos, 

 the result of primary, sudden, short-lived and lawless convulsion. "We do not 

 now connect the conception of irregularity with the history of the earth : it- 

 is the triumph of science to have analyzed that apparent chaos, and discerned 

 ord.i-r through it alL The mode by which this has been accomplished, it is 

 well known, has been the arrangement of cur terrene mountains according to 

 their relation to time : their relative ages determined, the course of our world 

 seemed smooth and harmonious, like the advance of any other great organiza- 

 tion. Ought we not then attempt to apply a similar mode of classification to 

 the formations in the moon hoping to discern there also a course of develop- 

 ment, and no confusion of manifestation of irregular convulsion? Professor 

 Nichol then attempted to point out that there appeared a practical and posi- 

 tive mode by which such classification might be effected. It could not, in so 

 far as he yet had discerned, be accomplished by tracing, as we had done on 

 earth, relations between lunar upheavals and stratified rocks ; but another 

 principle was quite as decisive in the formation it gave, viz., the intersection 

 of dislocations. There are clear marks of dislocation in the moon nay, the 

 surface of our satellite is overspread with them. These are the rays of light, 

 or rather bright rays, that flow from almost all the great craters as their cen- 

 ters, and are also found where craters do not at present appear. Whatever 

 the substance of this highly reflecting matter, it is evidently no superficial 

 layer or stream, like lava, but extends downward a considerable depth into the 

 body of the moon. In short, we have no likeness to it on earth, in the sense 

 now spoken of, except our great trap and crystalline dykes. It seemed clear, 

 then, that the intersection of these rays are really intersections of dislocations, 

 from which we might deduce their chronology. Can the intersection, how- 

 ever, be sufficiently seen? in other words, is the telescope adequate to de- 

 termine which of the two intersecting lines has disturbed or cut through the 

 other ? Professor Nichol maintained the affirmative in many cases, and by aid 

 of diagrams, taken down from direct observation, illustrated and enforced his 

 views. 



OX THE "IMATJYAISE TEHEES" OF NEBRASKA. 



The following is an abstract of a* paper on the above subject read at the 

 last meeting of the American Association by Professor James Hall: The 

 country on the Upper Missouri River Nebraska he said had been known 

 to us for many years ; but, until within a few years past, our knowledge had 

 been derived from Lewis and Clark, Nicolay, and some others. All these had 

 brought specimens from Nebraska, from which we have learned that for a 

 great distance along the Missouri River. ' :- ;' ming at the mouth of the Platte 



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