RECESSIONAL ICE BORDERS IN BERKSHIRE, MASS. 35 I 



Beginning at a point about three miles northeast of Tyring- 

 ham, the Becket moraine is readily recognizable as a continuous 

 line for a distance of twenty-five miles, or to a point two or three 

 miles northeast of Plainfield. The continuity of this line is 

 evident simply from the closeness of the moraine fragments of 

 which it is made up, and from its distinct separateness and lack 

 of confusion with the fragments of other earlier and later 

 moraines. The line of fragments stands out quite clearly as a 

 unit in Fig. 8, where no interpolation is employed. 



The other section is part of the Lenoxdale moraine. This 

 one has much larger tongues and re-entrants, and might at first 

 seem an unlikely case for clearly established continuity. But 

 its relation to Lake Housatonic fixes the contemporaneity of two 

 of its most widely separated tongues. As we have seen above,, 

 the great kame-and-delta terrace at Lenoxdale was built in a 

 lake. If there had been no obstruction in the narrow valley of 

 the Housatonic river below Glendale, the water would have 

 passed out by that course as it does now, and there would have 

 been no lake. There is another great karne-moraine deposit,, 

 with some delta gravel, at Glendale, showing conclusively that 

 the ice-border stood there also in a lake. More than this, at the 

 Konkapot col, three miles east of Great Barrington, there is the 

 head of a well-marked eroded river bed which was the outlet 

 of the lake in question, and this outlet is at an altitude of about 

 1,000 feet above the sea level — about the same as the top of the 

 fine sand in the Lenoxdale delta. There is also a beautifully 

 cuspate lake delta at East Lee at the same level, and the highest 

 part of the Glendale deposit stands at about the same. It 

 seems plain, therefore, that the ice-tongues at Lenoxdale and 

 Glendale stood in their places at the same time, and that there 

 was between these tongues a deep, wide re-entrant around Lenox 

 mountain. From Glendale to Hillsdale, N. Y., the closeness of 

 the moraine fragments and their distinct separateness from the 

 fragments of earlier and later lines leave no doubt of the con- 

 tinuity of the Lenoxdale ice-front. This section also is about 

 twenty-five miles long. 



The Becket and Lenoxdale moraines are roughly parallel,. 



