Dodge.] 388 [February 3, 



The following paper was read : — 



Notes on the Geology of Eastern Massachusetts. 

 By W. W. Dodge. 



By comparison with the prevalent line of strike in New England, 1 

 it appears that the eastern coast of New England forms a bay cut 

 into the parallel eastern strata. The head of this Gulf of Maine, 

 as it is sometimes called, is at Portland. The gneisses and schists 

 which lie fifteen or twenty miles from the coast in Massachusetts, and 

 stand out to sea in the form of long headlands and lines of islands in 

 south-eastern New Hampshire and southern Maine, seem to be con- 

 tinued to the north-east by similar rocks lying in Maine to the west 

 of the Penobscot River, on the other side of the gulf. 2 



East of the Penobscot, crystalline ranges extend north-easterly 

 through Washington and Hancock Counties into New Brunswick, 3 

 and are there associated with fossiliferous rocks, partly of the same 

 age as some of those associated with the rocks which, lying in a 

 band across the State, form the sea-coast in Essex, Middlesex, Nor- 

 folk and (northern) Plymouth Counties in Massachusetts. This 

 area in Massachusetts is the subject of the present paper. Its prob- 

 able original connection with that farther to the northeast makes it 

 important that they should be compared carefully, as each may throw 

 light on the other. 



The rocks of this vicinity may be treated in two groups: (1) the 

 crystallines, and (2) the more clearly stratified rocks among them. 

 In the absence of adequate knowledge of the ages of these groups, I 

 shall have to content myself with these very insufficient designations. 



I. Crystallines. 

 The rocks of this sea-coast area in eastern Massachusetts have 

 generally been described as " sienite and greenstone," from two 

 varieties which are very prevalent, and apparently in conformity 

 with the now antiquated terminology of the English Geological 

 Survey of half a century ago. 



iTkis prevalent line of strike, as is well known to geologists, maybe easily 

 determined on a common map by tke line of Hudson River, Lake Ckamplain, 

 .Richmond, Quebec, and tke south bank of the St. Lawrence to Gaspe", thus consist- 

 ing of two principal directions : north — south, and east-north-east — west-south-west. 



2 There are also similar rocks in south-eastern Massachusetts, in Plymouth and 

 Bristol Counties, which have the fiord formation on Buzzard Bay, strongly resem- 

 bling the appearance of the coast of Maine between the Kennebec and the Penob- 

 scot Rivers. 



s Proc. Am. Ass. Adv. Sci. (1867), Vol. xvi, p. 123. 



