I20 



Marvels of the Universe 



A fluffy, inchoate mass of light, itself indeterminate in shape and power, but appearing to be 

 castles, palaces and what not, glowing and fading, rising and falling apparenth' without reference 

 to the direction of the wind, but really acted upon by the lightest current of air ; rebounding from 

 the sea-surface as if it were a luminous bladder ; what could any primitive folk make of that ? I 

 very much doubt whether, if such a phenomenon were to be seen on our shores, we should not have 

 considerable terror among our fishermen and longshoremen, hard-headed and unromantic as we 

 know so many of them to be. So curious is this particular vagary of the Fata Morgana, that it 

 affords sufficient excuse for including it among the Marvels of the Universe. 



J'lio/o Jji] [fl. F. GicinneU. 



TWO SLABS OF FLEXIBLE SANDSTONE. 



The upper slab supported at its ends sags in the middle : the lower slab is supported in the middle and droops at each 



end : thus showing its elastic character. 



FLEXIBLE SANDSTONE 



BY RUSSELL F. GWINNELL, B.SC, F.G.S. 



" As firm as a rock " is a common mode of expressing stability, but here we have a case of a rock 

 which will bend Uke indiarubber. If a thin slab of this sandstone be hung downwards, the free 

 end can be made to swing to and fro like a pendulum while the upper end is held immovable. Not 

 only so, but as shown in the illustration, a slab will bend by its own weight when supported only 

 at the two ends or in the middle. 



The two specimens photographed are each about two and a half feet long and they show a 

 " sag " of the same number of inches. Their thickness is about an inch and a half. These 

 specimens from Kahana in the Punjab, India, are in the Geological Department of the Imperial 

 College of Science. 



Flexible rocks are distinctly rare, and the few known to occur are mostly sandstones ; an excep- 

 tion is the Magnesian Limestone of Darham, which very infrequently exhibits slight flexibility, and 

 is the only British rock possessing this character. 



Georgia and the Carolinas (U.S.A.) possess flexible sandstones, but the best known example 

 comes from Brazil, being found at Itacolumi, in the State of Minas Geraes. It is a porous yellow rock 

 made of grains of quartz (the chief constituent of most sands and the clear, hard mineral found in 



