example, the weight of which has been estimated at four million 

 tons. The diameter of the Arizona crater is about 4000 feet; that 

 of the Chubb is over three times greater. When the Chubb 

 meteorite walloped into the bare rock of the Ungava plateau it 

 must have set up a very considerable seismic disturbance. So 

 also must several of the others that landed in Canada. Now 

 meteorites are thought to be bits of some much greater body, 

 possibly a planet, that broke up or exploded somewhere within 

 our solar system, for they come in three major types — iron, iron- 

 rock, and rock. The actual chemical composition of these is odd. 

 in that among the iron and iron-rock types there are found some 

 minerals that do not exist on this earth. 



The falls of meteorites have been observed through the ages 

 and recorded since history was first written. Also, considerable 

 numbers of meteorites of all three classes, plus another type 

 known as glass meteorites or tectites. have also been found 

 scattered all over the surface of the earth, in most recent de- 

 posits. Meteorites have also been among the most holy and 

 therefore priceless collections of men since the Stone Age. 

 Further, large numbers of iron meteorites were "used up" by 

 primitive man before he learned to extract that metal from ores, 

 as has been shown by a chemical analysis of many of the earliest 

 iron artifacts so far discovered. Meteoritic iron seems to have 

 been man's first source of that metal. However — and this is the 

 really extraordinary fact — although iron and iron-stone mete- 

 orites seem, on a purely statistical basis, to have been falling 

 all over the earth at a regular though now diminishing rate 

 throughout historic and prehistoric times, not one single one or 



even tiniest part of one has ever been found in any of the 

 billions of tons of building stone, coal, salt, or any other rocks 

 or deposits that have now been mined by man for thousands of 

 years. The earliest known are from gravel and other compara- 

 tively recent surface deposits laid down not earlier than half a 

 million years ago; so it would seem that, prior to that time, no 

 meteorites fell on this earth. 



At the same time, working from quite another angle, there 

 are those investigators who have brought forward evidence to 

 show that, whatever large planetary body broke up to give rise 

 to the iron, iron-stone, and possibly stone meteorites, it did so 

 only about 300.000 years ago. Some of these investigators, along 

 with other scientists, have suggested that a planet between Mars 

 and Saturn then blew up, giving rise both to meteorites and to 

 the Asteroid Belt. Some of the resulting "junk" then for a period 

 crossed the path of our planet, which gathered it up slowly by 

 running into it and so clearing a path through it. The Moon, 

 because of its lack of atmosphere, acts like a vast broom as it 

 sweeps around the earth, covering a much wider front than we 

 do. Most of this debris was received by the Moon and because 

 of its lack of atmosphere was not burned up. Also, if its surface 

 is covered with deep ultrafine dust, even a small meteor might 

 make a tremendous impression on its surface. 



The pursuit of meteoritic craters can be fascinating, and their 

 discovery can yield some really unique insights into the vegeta- 

 tion, and thus into animal life; for they constitute the one truly 

 erratic and unpredictable physical force coming from outside 

 that may upset the even tenor of events on this earth. If they— 



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