120 GLACIAL GRAVELS OF MAINE. 



75 feet above the marine clay that covers its base. The top of the plain is 

 diversified with low ridges and some not very deep kettleholes, but the top 

 is so level, as seen from a distance, as to resemble one of the buttes of the 

 Rocky Mountains. After a gap of nearl}^ 2 miles a plain begins on the east 

 side of Union River, near the road from Ellsworth to Waltham. This- 

 plain is from one-fourth to three-fourths of a mile wide, and, with two 

 short gaps, extends to the cemetery, a short distance east of Ellsworth, 

 where it ends in a rather steep blufiP on all sides except the north. The 

 central parts of the plain, measured east and west, contain cobbles and 

 bowlderets; to the very south end of the plain, but on the east and west 

 margins pass into fine gravel and finally into sand. This plain thus is seen 

 to diff'er much from, the typical delta, yet shows some horizontal assortment 

 of sediments, as if the channel within the ice was by degrees enlarged so 

 much toward the east and west that the velocity of the current was checked 

 in it — indeed, it practically formed a lake within the ice. South of this point 

 there is another gap of a mile or more, and then a broad ridge or plain, 

 interrupted by a few short gaps, extends southward through Hancock, past 

 North Lamoine, and ends not far above sea level near East Lamoine, right 

 opposite Mount Desert Island. Toward the south the gravel becomes finer 

 and soon passes into sand, which is good for building purposes, and large 

 quantities of it are shipped to Bar Harbor and along the coast. The plain 

 does not become fan-shaped, but remains only from one-eighth to one-fourth 

 of a mile wide. While, then, we see the horizontal classification of sedi- 

 ments characteristic of the delta, yet this is not the radiating shape of a 

 plain deposited in the open sea, when it was free to spread in all directions 

 under the action of winds and tides, as it would have been on the rather 

 level plains of Lamoine. These facts warrant the interpretation that the 

 glacial waters were flowing in a broad channel which opened on the sea and 

 formed a sort of bay or estuary, bordered by ice walls at the sides. 



Some of the gaps in this system are pretty long, yet the linear 

 arrangement of the several deposits is such that there can be little doubt 

 they were all deposited by a single glacial river, with perhaps one or two 

 tributary branches. The largest marine delta of the system is situated in 

 Otis, above 175 feet elevation and below the contour of 230 feet. 



The length of the system is about 27 miles. 



