GIBB A CHAPTER ON FOSSIL LIGHTNING. 



195 



A CHAPTER ON FOSSIL LIGHTNING. 



By G. D. GiBB, M.D., M.A., F.G.S., Member of the Canadian Institute. 



The expression fossil lightning" may seem somewhat paradoxical, 

 but it is here employed in a figurative sense to designate a condition 

 of things which we have good modern evidence to prove to have been 

 the result of the lightning's flash, myriads of ages gone by. Of late 

 years vitrified sand-tubes have been discovered in Cumberland, in 

 Prussia, South America, Natal, and other places ; and these have been 

 very clearly made out as having been directly caused by lightning, 

 and hence they have been called by mineralogists Fulminary tubes" 

 or Fulgurites. All these would appear, so far as we can ascertain, to 

 have been formed at comparatively a very recent period, and hardly, 

 therefore, deserving of the appellation of "fossil lightning." Never- 

 theless, as I have come across some examples of such bodies on the 

 surface of the flagstones which form our pavements, and of the an- 

 tiquity of which there cannot be any doubt whatever, I have no 

 hesitation in making use of the term which iieads this chapter. 



If I had at one time any scruples upon this point, they were re- 

 moved whilst attending the instructive lectures so eloquently delivered 

 by that great philosopher and distinguished comparative anatomist, 

 Professor Owen, at the Museum of Practical Geology, in the early 

 part of the last year. He used this expression, in his first lecture on 

 Fossil Birds, when particularly speaking of the various modes in which 

 the evidences of evanescent things become recognisably preserved 

 in rock, as illustrated by meteoric phenomena, footprints, soft and 

 soluble plants, and animals. The " fossil lightning," as exhibited in 

 the British Museum, he lucidly described, and pronounced some of it 

 even to be forked. As further illustrating evanescence, I may for the 

 moment refer to some specimens of rain-prints and shrinkage-cracks 

 on the under side of layers of carboniferous sandstone from Cape 

 Breton (Nova Scotia), figured and described by Sir Charles Lyell, in 

 the Geological Society's Journal and in his "Manual of Geolog}^" 

 The large size of the rain-drops would indicate most probably a vio- 



