360 GLACIAL GRAVELS OF MAINE. 



as a discontinuous osar, we need some term to apply to the separate 

 mounds and ridg-es, and for such purposes I employ the word "esker." 



The gravel masses have various external features, such as continuity 

 or discontinuity, narrowness of ridge with arched cross section or breadth 

 with horizontal cross section, reticulations, etc., which have to be described 

 by the use of various modifying terms. 



It is often a doubtful question how far local usages of language ought 

 to be followed by geologists. For instance, the word "plain" is in very 

 common use in Maine to denote rather level or gently rolling tracts of gla- 

 cial gravel and sands, generally with some definitive, such as "Norway 

 plains" (meaning tracts of reticulated kames OA^ergrown with yellow or 

 "Norway pines"), " checkerberry plains," "blueben-y plains," "Litchfield 

 Plain." In all these cases popular usage has recognized that these "plains" 

 are tracts of sand or gravel differing in composition from the soils of the 

 surrounding regions; and since they are much more level than the hills, 

 they come to be known as "plains," even though they as little deserve the 

 title "plains" as do the Great Plains west of the Missouri River. It is 

 doubtful if geologists can go to Maine aiid inquire their way to many of 

 the localities and deposits described in this report without employing the 

 word "plains" in their inquiries. While it may be conceded that in strict 

 geological language it is desirable to use the word "plain" only where it 

 has a natural geometrical application, yet there are disadvantages in cutting 

 entirely loose from local usage. 



On reflection, instead of the term "osar-plain" for the broad osar, the 

 term "osar terrace" will often be used, partly because the term "moraine 

 terrace" was used many yeai's ago by Prof. C. H. Hitchcock^ to distinguish 

 reticulated masses of glacial gravel. 



GLACIAL GRAVELS AS MODIFIED BY THE SEA. 



I assume that all the outer coast of Maine below the contour of 225 

 feet, perhaps below that of 230 feet, was under the sea during the last part 

 of the Glacial period. In the interior of the State the sea must have stood 

 at a somewhat greater height in the principal river valleys, then deep bays. 



In general the glacial gravels that were under the sea at an}^ time are 

 somewhat different in external form from those situated above the former 



' Preliminary Eeport upon the Natural History and Geology of the State of Maine, p. 270, 1861. 



