CHAPTER V 

 THE CONNECTIONS 



The connections of varve curves, as explained on page 4, are 

 based on agreement among them. Accordingly, it is after all 

 a matter of personal judgment whether connection is found or 

 not. The personal factor, however, can be practically eliminated 

 by only accepting fine and persistent agreement among relia- 

 ble graphs. The greater the number of graphs which are found 

 to agree, the more certain is the connection. Since the clay 

 sedimentation, i. e. the curves, reflects the climatic fluctuations, 

 and since these are periodical, characteristic features in the 

 graphs often recur somewhat different or exactly similar. But 

 the correspondence, as a rule, persists only for a small group of 

 varves, so that if the profiles are not too short the danger of mis- 

 connection is avoided. 



Value of Varves for Study According to 

 Their Characteristics 



The value of the varve clays for chronological studies varies 

 gready. The best varves are one to two inches thick and consist 

 of a silty, light-colored summer layer and a greasy, dark winter 

 layer. They are easy to measure and give the most typical 

 curve. Thick varves are generally good, so long as they do not 

 contain coarser material than silt, but they show sometimes too 

 great annual fluctuations. When they contain sand, they are 

 not reliable, since they then are often entirely too thick and 

 always show exaggerated variations from year to year. Such 

 varves indicate drainage of ice-ponded lakes or deposition close 

 to the ice edge or in strong current or in too shallow water. Very 

 thin varves, besides being difficult to measure, give a curve which 



