CLIMATOLOGY. 301 



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lished — by Ragnar Liden in the valley of the River Angermanalven (63° N.) 

 is based upon annually laminated silty clays deposited in fiords of the Gulf of 

 Bothnia ever since the disappearance of the last ice sheet. The annual 

 deposit consists of two thin layers, the upper dark gray zone of which, the 

 equivalent of the winter layer in the glacial varve clay, is essentially deposited 

 in connection with the flood of the rivers during the melting of the snow in 

 spring. By upheaval of land amounting to about 900 feet the clays have been 

 gradually raised above sea-level and trenched by the rivers. Those from the 

 last hundreds of years, are not yet accessible, and Liden has had to estimate 

 the length of time that has elapsed since the formation of the youngest meas- 

 ured varve or annual layer. 



This gap in the record might be bridged by help of the sequoia curve, for it 

 seems likely that it will show certain correspondence to the sedimentation 

 curve in Norrland. The climatic stress during the fourteenth century, so 

 distinctly recorded in the sequoia curve, is probably also recorded in the clay 

 deposition. If this prove to be the case, and also other marked fluctuations in 

 the tree curve will be found in the clay curve, a connection may be made with 

 high degree of probability, and the length of the post-glacial time, which 

 amounts to about 8,500 years, exactly determined. 



Huntington, Ellsworth, Yale University, New Haven, Connecticut. The big 

 trees as a climatic yard-stick. (For previous reports see Year Books 

 9, 10, 11, 14, 15.) 



The purpose of this investigation was to test the supposed relationship 

 between rainfall and the growth of the Big Trees by means of correlative 

 coefficients. It was found that while there is a positive and significant 

 correlation between tree-growth and the rainfall at Sacramento, the nearest 

 station with a long record, there is much stronger correlation with the rain- 

 fall at Baor, a station on the Southern Pacific railroad at about the altitude 

 of the trees. The strongest correlation is between the trees and the rainfall 

 at Jerusalem. Farther west in the Mediterranean this dies out. A com- 

 parison of the rainfall at Bora with that of stations in all parts of the United 

 States indicates a decided contrast between the southwestern and south- 

 eastern States, the rainfall tending to decrease in the southwest when it 

 increases in the southeast and vice versa. The general conclusion is that 

 the Big Trees, when studied by the method of correlative coefficients, show 

 that they can properly be used as a climatic yardstick for certain areas in 

 various parts of the world, but not for other intervening areas. 



Another phase of the present study indicates that the rainfall of the 

 second or third year previous to the growth of the trees has the greatest 

 effect on growth. Where trees grow in moist places the rainfall for as long 

 as ten years has some effect. 



