Pace Ten 



EVOLUTION January, 1928 



How Old is the World? 



By Allan Strong Broms 



Some Fundamentalist Versions 



JAMES USHER, Archbishop of Armagh, 

 set the date of creation in the year 

 4004 B. C. Dr. John Lightfoot, Vice- 

 Chancellor of Cambridge University, "im- 

 proved" this dating by fixing the week of 

 creation for October 18th to 24th, so that 

 Sunday, the 25th, became the first day of 

 hard earned rest. But later scholars, of equal 

 "authority", have placed the date variously at 4710 

 B. C. and 5872 B. C. So, after all, the doctors 

 of divinity disagree and we may, without offense, 

 consider 



Some Scientific Versions 

 In a rear storeroom of the American Museum of 

 Natural History in New York, I was one day 

 privileged to examine a collection of banded clays 

 carefully preserved with glycerine in long metal 

 pans. From them, Dr. Chester A. Reeds and 

 other scientists were reconstructing the history 

 of the New Jersey, New York and New England 

 areas at the close of the Great Ice Age, long be- 

 fore the coming of the white man. They already 

 had a complete year by year record covering thou- 

 sands of years, indicating a date for the melting 

 away of the ice sheet perhaps more than ten 

 thousand years ago, but so far not definitely con- 

 nected with modern dates. One of them, Dr. E. 

 Antevs, was, however, busily gathering samples of 

 clay from Canada for that very purpose. He was 

 trying to fix definite dates for the various stages 

 of melting and retreat of the ice sheet which 

 once covered nearly all Canada and much of the 

 northern United States. 



His hopes of success rested upon a previous suc- 

 cess elsewhere. He had assisted Baron Gerard De 

 Geer, the Swedish geologist, in applying a new 

 method for finding the dates of retreat of the 

 Baltic Ice Sheet which had invaded the Scandina 

 vian countries, Finland and parts of Germany and 

 Russia. They had fixed dates as early as 11,600 

 B. C. and connected them definitely with our own 

 calendar dates. 



When the long cold spell which caused 

 the Great Ice Age came to an end, the 

 edge of the ice sheet melted back as 

 though retreating. Here and there 

 along its front, pools and lakes of icy 

 water would form. These waters of melt- 

 ing would be muddy with silts and gravels. 

 During the warm summers, when melting 

 was rapid, the swift flow of waters would 

 carry away the finer silts, but let the 

 coarser gravels settle in the lake bottoms. 



Like the Rings in a Tree 



When the cold of winter stopped the melt- 

 ing, the flow of waters would slacken and 

 permit the finer silts to settle slowly and 

 form a dense layer of darker clay. Each 

 passing year would therefore be marked 

 by two alternating layers of gravel and 

 clay, each pair being a yearly cycle or 

 "varve". The principle is exactly the 

 same as that by which we measure the age 

 of a tree by the number of rings of 

 growth. 



THE GREAT CLAY 

 CALENDAR 



Banded Glacial 



From New Haven, 



Collected by Dr. E. 



Clay 

 Conn. 



Antevs 



Fortunately the layers are not all alike, 

 but can be positively distinguished and 

 identified over wide areas. During an ex- 

 ceptionally warm summer, a deeper gravel 

 layer might be formed or other distinctive 

 variations appear. The annual deposits 

 in one lake can thus be identified with 

 '.hose in other lakes nearby and by going 

 from one to another, a complete series for thou- 

 sands of years may be worked out. In fact, they 

 have been traced to the very fronts of existing 

 glaciers in northern Sweden (where just such 

 layers are now being laid down each year), and 

 so connected with our own times. 



Obviously, no layer could be formed at any 

 point until the ice had melted from the region. 

 The edge of a layer of any date, where it 

 touches bedrock, will therefore mark the edge of 

 the ice sheet at that date. By this method, the 

 stages of retreat of the Baltic Ice Sheet have 

 been carefully dated as shown on the map. The 

 entire record goes back some 13,500 years, long 

 before the Fundamentalist's date of creation. 



Plenty of Years for Evolution 



But more than this, the ice sheets must have re- 

 quired tens of thousands of years to accumulate, 

 lor they were probably a mile thick in places. 

 Furthermore, the geologic records show that there 

 have been many such ice invasions, separated by 

 periods of warmth as long or longer than our own. 

 So we may safely assume, for the Ice Age as a 

 whole, not merely tens, but hundreds of thousands 

 of years. . Nor is this all, for underneath the 

 rubbish left by the melting ice sheets, which is 

 really very thin upon the deep earth crust, are 

 records indicating an earth age of millions of 

 years. At least we may be satisfied that there is 

 no poverty of years for the slow evolution of life 

 upon the earth. 



(In oar next issue Mr. broms will explain how 

 scientists measure the age of the earth from the 

 radio activity oj uranium and thorium.) 



Retreat oj glacial ice sheet 



DOES SUCCESS BREED CHILDREN? 

 HPHE loud wailing set up by eugenists to 

 the effect that people with the best 

 minds tend to have the fewest children, 

 while the most ignorant reproduce most 

 abundantly, ought to be toned down a 

 little, according to Dr. Frederick Adams 

 Woods, formerly professor of biology at 

 Massachusetts Institute of Technology. 



At least, he says, among college gradu- 

 ates who have been out of Harvard Uni- 

 versity for twenty-five years or more, it is 

 the successes who have the most children. 

 He took as an arbitrary measure of suc- 

 cess a place in Who's Who in America- 

 Dr. Woods found that 25.5 per cent, of 

 the parents with four or more children in 

 the class of 1894 were listed in Who's Who. 



