6 Field Museum of Natural History — Geology, Vol. V. 



longer ones are curved. Except at one point the striae are confined to 

 one side of the ridge, the perpendicular side shown in Plate III. On 

 the other side of the ridge a small area shows striae running parallel with 

 the ridge and directed toward the boss. The ridge evidently served to 

 deflect the air current on the perpendicular side at right angles, but on 

 the other side, which was flatter, their normal, radial course was little 



Fig. I. Diagram showing how erosion by air currents tends to produce a conical 

 form in a falling meteorite. 



changed. The striated side of the ridge is also smoothed and presents 

 generally convex rather than concave surfaces. Further, the slopes of 

 the secondary depressions on this side are abrupt rather than gradual. 

 Besides this main ridge, several smaller ridges produced by the meeting 

 of broad depressions appear on the front surface of the meteorite, and 

 besides the broad depressions "and striations of the front surface there 

 may be noted deep, narrow pits and crevices which penetrate into the 

 mass of the meteorite. The longest of these is shown near the upper 



