hammatt NATURE-STUDY AT QUANSET 133 



place in the bar or barrier beach formerly the outlet of Pleasant 

 Bay, where in bad storms the waters break through. Here a line 

 of old telegraph poles below high water half covered with the 

 sands of the beach tells its own story of the washing away by the 

 winds and waves of the sand bluff. At the Nauset Life Saving 

 Station is a steep bluff . The storms of the winter before had laid 

 bare in the bluff an ancient peat bed. In it are preserved the old 

 tree trunks that helped to form it. Beetles wings, brought to 

 light in the peat beds, crumble to dust when the air strikes them. 

 They hear that valuable specimens of the "hind wing" have been 

 found in the Harwich woods. They plan to go out and sugar for 

 moths. 



Under the soil of the greater part of the continents and even 

 of the ocean floor, bed rock is found. But under the glacial soil 

 of Cape Cod, no such bed rock has been discovered, either in ex- 

 posed cliffs or in deep well borings. 



"The cape" then, has no backbone of rock. But how did it 

 get here? 



Geologists explain its presence something as follows. 



Once on a time (geologic time), when ice sheets covered great 

 parts of our country and ground their way slowly but surely down 

 from the frozen north, south and southeasterly over New England, 

 there were three such glaciers hereabouts. One filled Cape Cod 

 Bay, one filled Buzzard's bay and spread toward the west, while 

 the third, a hugh one, stretched way out into the ocean to the east 

 of Cape Cod. 



As the Cape Cod glacier pushed its way slowly south, it scooped 

 out the sea floor to make the bay and, as its edge melted, there 

 slid and dropped from it, here an immense mass of gravel and boul- 

 ders, there a huge heap of sand, clay and rocks. This shows as 

 a mixture of coarse and fine material not seen where it has been 

 sorted by water. In the latter case the coarser material is dropped 

 first, and the finest of all is kept longest in suspension. Water 

 sorted material is stratified, the lines or strata plainly visible. 



Glacial boulders may be seen on the tops of the hills and else- 

 where on the Cape. Enos' Rock or Enoch's Rock is a well known 

 example. 



All this material dropped by the glacier, it had collected in 

 Labrador, or Vermont or Massachusetts (we can tell by the kind 



