398 NOTES ON THE LIZARD BOCKS. 



The weight of the slice without magnetic influence was 76 

 grains, to test its attractive powers I placed the magnet over it, 

 when the weight was reduced to 72 grains, on applying it under 

 the slice, it increased to 80 grains ; this proved an affinity of 

 4 grains, either way. 



The various rocks referred to extend over an area of 50 

 square miles, and probably vary from 50 to 500 feet in thickness. 

 Here is magnetism in magnitude, food for contemplation, dread 

 for the mariner ; but a grand field for the mineralogist. 



