30 SEASON AL DEPOSITION IN AQUEO-GLACIAL SEDIMENTS. 
lumps of clay in the deposits above the clays; erosion of clays; and glaciated 
pebbles and boulders on the surface; but in most places the evidence indicates 
that these upper sandy beds lying on the clays were contemporaneous with the 
ice advance. 
Banding appears to be lacking in these clays at certain places to the east 
of the pit now in active operation. The cause of this lack of layers has not 
been determined. 
In regard to the alternations in the layers at Barrington, Shaler wrote: 
“The cause of these alternations has not been found. It may have been connected with 
the seasonal variations in the flow of water from the ice front and the consequent carrying 
power of the streams which did the work. In some sections there is a curious likeness in the 
thinness of the layers which suggests some such action.”’ SHALER, 1896, p. 968. 
If the banding in the clays means seasonal deposition there are at least 
500 years represented in the small section exposed in the Barrington clay-pit. 
If the whole sixty feet of clays should have an average thickness of one fourth 
of an inch for seasonal deposits the years represented would be not less than 2,800 
at this locality. 
At Barrington, as has been noted, the fine components in the banding are 
very thin compared with the coarse components. This may mean compara- 
tively shallow water or a short winter season. There is no indication of ripple 
mark. The water was not very shallow, probably not less than thirty feet 
deep when the latest clay units were deposited. It is also possible that the 
glacial streams here contained very little of the fine clay material. 
