68 •/. B. Wood worth — Post- Glacial 



gravels. This layer could be traced for a long distance either 

 side of the point where I crossed the ditch, and thousands of 

 characteristic facetted pebbles may be obtained from the layer. 

 It was a noticeable fact that no facetted or polished pebbles 

 occurred in the exposed faces of the underlying gravel section. 

 The geological conditions of this section lend support to the 

 idea that facetted pebbles are the product of eolian action. 

 The location of this eolian pebble bed out on the southern 

 margin of the frontal plain of the Martha's Vineyard moraine 

 and on a surface which bears no marks of ice-advance excludes, 

 it seems, the agency of strictly glacial causes from effecting 

 the shape of these pebbles. They are evidently glacial stream 

 pebbles reshaped in situ. 



. In the many instances on this island of soil-covered sur- 

 faces which have evidently undergone exposure to wind-blown 

 sands, I am not certain of the time of the action, for it is ob- 

 vious that since the process is now going on in places, so it may 

 have been active at any time in the past, the process being 

 interfered with by the renewal of the vegetative coating. But 

 the wide spread occurrence of buried or partially inhumed 

 eolian pebbles, with worn sand, points strongly to the conclu- 

 sion that the process has been more active than it now is. 



Providence atlas sheet. — On the surface of the sand-plain in 

 East Providence, P. I., is a bowlder 3 feet in length and 2 

 feet high, the southern face of which has been scored, worn 

 and polished, evidently by the long continued action of blow- 

 ing sand. The surface about the bowlder is now grass-covered. 

 South of Providence in Auburn, bowlders exhibit traces of 

 the same action. In many places on the west side of Narra- 

 gansett Bay, the surface is covered by blown sand. 



Boston atlas sheet. — Eolian pebbles occur in the soil near 

 Fresh Pond in Cambridge. The pebbles of the Poxbury 

 conglomerate, in a ledge, in Dorchester, exhibit the peculiar 

 spoon- shaped and polished surface due to wind-erosion. Carved 

 slates occur on the surface of kames in the soil along the 

 Charles Piver in the vicinity of Mt. Auburn cemetery. 



Boston Bay atlas sheet. — A bowlderet 6 inches in diameter 

 bearing crateriform faces and possessing a high polish was 

 found on Grover's cliff in Winthrop, the cobble having come 

 evidently from the upper surface of the drumlin. 



Narragansett Bay atlas sheet. — Eolian pebbles occur near 

 the head of a glacial sand-plain half a mile north of the War- 

 wick Keck Station in Warwick, P. I. 



Dedham atlas sheet. — I found a pitted eolian pebble on the 

 surface of a kame at Holbrook station on the Old Colony rail- 

 road. 



