FOSSILS IIST THE EAISED BEACHES. 53 



4. The lieach was more or less protected hj shore ice. 



5. The surf probably beat against the ice during all the time of its 

 advance and until the ice had retreated north to the central part of ]\Iaine. 



The net result of these causes was that recognizable beaches are found 

 only at intervals. Most of that portion of Maine below 230 feet affords 

 either no beach gravel or only scant quantities of it. 



It follows from the above that the finding of a sea wall across a valley 

 at a certain elevation, or of a beach terrace on a hillside, would not neces- 

 sarily indicate a long pause of the sea at that level unless the relief forms 

 of the adjacent land show that the sea waves would have as easy access at 

 other levels as at that. The fact that those valleys of most uniform slope 

 and exposure to the sea do not show well-defined beach terraces proves that 

 at least the fall of the sea proceeded at a nearl}' uniform rate, unless the 

 pauses at 225 to 230 feet and at 20 feet be exceptions. 



FOSSILS IN THE RAISED BEACHES. 



On the western slopes of Munjoy Hill, Portland, as pointed out to me 

 by Mr. C. B. Fuller, the impressions of various shells and the burrows of 

 divers moUusks, etc., are traceable in sedimentary sand and fine gravel at 

 elevations of 50 or more feet above the sea. The top of the hill is covered 

 with a sheet of glacial gravel, and the fossils are in beds which are stratified 

 parallel with the slopes of the hill. The hills of Portland would not be 

 in the most exposed situation when the sea beat upon their upper portions, 

 yet there would be enough of a surf to erode considerable of the glacial 

 sand and gravel from the top of Munjoy Hill. On the whole, I consider it 

 more probable that the glacial sand and gravel containing fossils is not in 

 the condition it was in when deposited by the glacial streams — that it was 

 changed to beach matter by the waves of the sea, which washed it from the 

 top of the hill and deposited it on the lower slopes. On the modern gravel 

 beaches most, if not all, of the shells are being pulverized so rapidl}^ by 

 the beating of the surf that it is doubtful if many of them sur\'ive long 

 enough to become embedded in the beach matter, unless it be below low tide. 

 In several parts of the State I have examined excavations in the high 

 beaches at 200 feet and found no shells and no impressions or casts of fos- 

 sils large enough to be recognized by the unassisted eye, and no burrows. 



