304 ANNUAL REPORT SMITHSONIAN INSTITUTION, 19 30 



With samples of the material in hand the correlation is often 

 effected by a comparison of the variations in thickness, color, or 

 peculiar lamination of successive varves or groups of varves. The 

 seasonal and yearly variations are also noticeable when measuring 

 the thickness of the sediments in the field on strips of paper. Their 

 relative values, however, are made more apparent when plotted 

 graphically, according to a method initiated by Gerard de Geer, of 

 Sweden, in 1906. The diagram consists of a horizontal base line 

 from which arise a number of vertical lines spaced one-half centi- 

 meter apart. These equally spaced lines on the abscissa are numbered 

 to represent the varves or years. The thickness of the successive 

 varves from the bottom upward are entered as ordinates from left 

 to right on the successive vertical lines and the tops united with one 

 another to make them stand out more effectively. A comparison of 

 such diagrams representing different sections brings out whether they 

 are common varves and how they are related to one another. 

 (Fig. 2.) 



Varved clays are extensively represented in the Pleistocene epoch 

 (De Geer, 1910, 1912, 1921, 1926, 1927a, 192T5 ; Antevs, 1922, 1925, 

 1928; Norin, 1927; Keeds, 1926, 1927; Sauramo, 1923, 1929; Sayles, 

 1919). They are also represented in glaciations older than the 

 Pleistocene (Antevs, 1925; Reeds, 1923; Sayles, 1914; Schuchert, 

 1914; Sussmilcli and David, 1919). 



FLUCTUATIONS IN HAVERSTRAW AND NEW HAVEN VARVED CLAYS 



In order to investigate the possible relation between varved clays, 

 glaciation, and weather, the laminated clays at Haverstraw, N. Y., 

 and New Haven, Conn., have been measured, correlated, and specially 

 diagramed. The Haverstraw clays extend along the west bank of 

 the Hudson River from a mile south to 2 miles north of the town and 

 reach inland one-half mile from the river front. These clays vary 

 in thickness from 50 feet in a 60-foot terrace facing the Hudson 

 River in west Haverstraw to more than 100 feet in the low plain 

 bordering the river bank. The New Haven clays occur in the low- 

 lying Quinnipiac River Valley, in the eastern portion of the city. 



The varves in the Haverstraw clays were measured, correlated, and 

 diagramed by Chester A. Reeds and Ernest Antevs, working inde- 

 pendently. The Reeds diagram of 736 varves was shown and accom- 

 panied by abstracts at the Cleveland, 1927, meeting of the Geological 

 Society of America, while Antevs' Haverstraw curve appeared in 

 March, 1928, in his book. The Last Glaciation, published by the 

 American Geographical Society, Research Series No. 17, as graphs 

 marked New Haven Al, Bl, Plate I; A2, B2, A3, B3, A4, Plate 11. 

 The New Haven varved clays, which Antevs correlates with Haver- 



