OLD CONTINENTS. 573 



It would be unwise to theorize at present on a result so remark- 

 able. Nor can we assert that Herschel's speculations have been con- 

 firmed, though his general reasoning has been abundantly justified. 

 Astronomers have yet to do much before they can interpret the mys- 

 terious entity which adorns Orion's sword. On every side, however, 

 observations are being made which give promise of the solution of 

 this and kindred difficulties. We have seen the light of comets 

 analyzed by the same powerful instrument ; and we learn that the 

 ligbt from the tail and coma is similar in quality (so far as observation 

 has yet extended) to that emitted from the Orion nebula. We see, 

 therefore, that in our own solar system we have analogues of what has 

 been revealed in external space. I would not, indeed, go so far as to 

 assert that the Orion nebula is a nest of cometic systems ; but I may 

 safely allege that there is now not a particle of evidence that the 

 nebula lies beyond our galaxy. 



Nor need we doubt the accuracy of Lord Rosse's observations. 

 More than a year before his death, indeed, he mentioned to Dr. Hug- 

 gins that "the matter of the great nebula in Orion had not been re- 

 solved by his telescope. In some parts of the nebula he observed a 

 large number of exceedingly minute red stars. These red stars, how- 

 ever, though apparently connected with the irresolvable blue material 

 of the nebula, yet seemed to be distinct from it." 



The whole subject seems to be as perplexing as any that has ever 

 been submitted to astronomers. Time, however, will doubtless un- 

 ravel the thread of the mystery. We may safely leave the inquiry in 

 the hands of the able observers and physicists whose attention has 

 been for a long time directed toward it. And we need only note, in 

 conclusion, that in the Southern Hemisphere there exists an object 

 equally mysterious the great nebula round n Argus which has 

 yielded similar results when tested with the spectroscope. The exam- 

 ination of this mysterious nebula, associated with the most remarkable 

 variable in the heavens a star which at one time shines but as a fifth- 

 magnitude star, and at another exceeds even the brilliant Canopus in 

 splendor may, for aught that is known, throw a new light on the con- 

 stitution of the great Orion nebula. Fraser^s Magazine. 







OLD CONTINENTS. 



By Peof. A. C. EAMSAY, 



OF THE ENGLISH GEOLOGICAL SURVEY. 



FOR many years the stratified formations in general were de- 

 scribed in manuals of geology as of marine origin, with the 

 exception perhaps of part of the Coal-measures, and more unequivo- 

 cally of the Purbeck and Wealden beds, and the fresh-water strata 

 of parts of the Eocene and Miocene series. Even now the Old Red 



