370 PROCEEDINGS OF THE NATIONAL MUSEUM. vol, 58. 



Plate 23. 



estherville, iowa, meteorite. 



Fig. 1. Micro-section showing general structure. The colorless areas with very 

 irregular borders and no cleavage are anorthite. The black are metal and 

 metallic sulphide; others olivines and pyroxenes. 



2. The same under somewhat higher magnidcation and showing feldspars with 



clouded interiors and clear borders. 



3. The same showing a single feldspar in matrix of pyroxenes. Note the rounded 



form of nucleal portion of the feldspar and the bubbles projecting from this 

 portion into the clear border. The crystal extinguishes as a unit with the 

 exception of a portion of the margin, at the lower right. 



Plate 24. 



estherville, iowa, meteorite. 



Polished slice in cabinet of University of ^Minnesota. Approximate dimensions- 

 20 by 33 cm. 1 and 2, pebble-form masses of enstatite; 3, pebble-form mass of 

 'peckhamite"; 4, metal; 5, cavities. 



