233 



arc, of course, y;rciitly broiulciietl by the relatively low dip.s ; 

 and there is nothing to show conclusively with which [)art of 

 the Beal's Cove section, for example, they should be identified. 

 No dips, however, have been observed south of the slate ; and 

 it is possible that the low and wavering dip of the slate itself 

 should be intcr[)retcd as marking a synclinal axis, the sand- 

 stone and conglomerate on the south being a repetition of that 

 on the north. The conglomerate could then, perhaps, be 

 correlated with the first great bed (3) and regarded as passing 

 u[) over the mela[)hyr, which would thus mark an anticlinal 

 axis ; and we should be able to dispense with the fault between 

 the conglomerate and melaphyr. 



The Melville Garden and Planter s Fields Area. 



Tliis area embraces the district east of the Unit's (^ove 

 melaj)hyr and north of the great dike and Otis Hill, including 

 a large part of the tract known as Planter's Fields, Melville 

 Garden, Pleasant Hill, the smaller drumlins forming Crow 

 Point, and the adjacent islands of Hingham Harbor — Kagged, 

 tSarah, and Langlee. From the western base of Pleasant Hill 

 eastward, north of Melville Garden, to Downer Landing, 

 tlie drundins are continuous, as shown on the general map, 

 and the hard rocks are wholly concealed ; while curving around 

 the south and west sides of this drift area, as previously 

 noticed, is a well-exposed belt of strata, the third and last 

 general section of the conglomerate series. 



The most perfect outcrops are those afforded by the islands,^ 

 which, it may be noted in passing, are a beautiful illustration 

 of the dependence of relief upon geologic structure. The shores 

 of these islets are almost continuous exposures ; and the atti- 

 tude of the strata is exceedingly constant, the strike being nearly 

 due cast-west and the dip S. 35°— 40°. Langlee Island is an 

 approximately rectangular mass 600 feet long and 400 feet 



I See the uncolored special map (PI. 10). 



