THE WILLAMETTE METEORITE 113 



discovered only when the thick rust and scale within them had 

 been removed. The bottoms of the great cavities extend to 

 essentially the same plane, about 18 inches below the general 

 external surface. 



Between the cavities there are hourglass-shaped pillars with 

 nearly flat tops in which are many small flask-shaped holes three 

 or more inches deep with orifices half an inch to one and one-half 

 inches across. These are arranged in definite lines extending 

 obliquely across the base of the meteorite in two directions 

 nearly at right angles to each other. The great cavities are 

 arranged in corresponding manner with their longer diameters 

 parallel to one or the other system of lines of small holes. The 

 character and arrangement of the cavities on the rear side of 

 the meteorite indicate clearly that we have here a result of 

 decomposition and erosion. Exactly analogous pits and cavities 

 have been observed in beds of limestone and gypsum, where there 

 can be no doubt of their erosional origin. 



The climate of the region where the meteorite was found is 

 extremely moist, without excessive rainfall, and there is com- 

 paratively little snow and ice, hence the conditions are excep- 

 tionally favorable to rapid oxidation and disintegration. The 

 land is forest-covered, so that humus acids and carbonic acid are 

 supplied in abundance to assist the destructive work of the 

 water. The process seems to have been a simple one, the 

 nodules and rods of troilite which are scattered through the mass 

 having formed centers of ready attack for the oxidizing agents. 

 These areas of troilite have been near enough together in certain 

 directions to lead to the speedy coalescence of the cavities pro- 

 duced and the consequent formation of the great elongate basins. 

 Troilite nodules may be seen now in several of the cavities. 



The cylindrical holes are somewhat irregular in their shape 

 below the orifice. They are from ii to 3 inches in diameter and 

 of varying depth up to 6 or 8 inches. They show most clearly 

 in the illustration on page 107 along the upper rim of the mete- 

 orite. These holes resemble the bore-holes of Canyon Diablo, 

 Chupaderos and other iron meteorites, and are thought to have 

 been begun by fusion or erosion of rod-like masses of troilite. 



The small, shallow depressions which Professor Ward has 



