Cro*by.] 
506 
[May i8, 
the geological structure of the several areas may he noticed here,., 
referring to the forthcoming Occasional Paper, for full descrip- 
tions of the ledges. 
THE VILLAGE AREA. 
In the Village Area (PI. XIV) the most continuous exposures are 
in the vicinity of Hersey Street, the section here being almost 
unbroken for about 800 feet and showing several alternations of 
conglomerate, sandstone, and red and gray slates, all dipping 
steadily S. 70°. The most of the beds in the Hersey Street section 
can be traced east by satisfactory outcrops, and with a marked 
change of strike, to Lafayette Avenue and Elm Street; and the 
structure is rendered much more complicated and interesting by 
the appearance in the midst of the sedimentary rocks of a consider- 
able body of granite enclosing a large dike of diabase. The facts 
lend no support whatever to the view that the granite is intrusive 
in the conglomerate and slate ; but- they point very clearly to the 
conclusion expressed on the map, viz., that the granite is bounded 
by compensating faults and marks a local uplift. In the absence 
of outcrops, it is impossible to determine how and where the 
Village belt of strata terminates on the east. It is probable, how- 
ever, that it crosses Main Street, passes beneath the sand plain 
occupied by the cemetery, and ends in the Home Meadows, against 
the great boundary fault between the Hingham and Xantasket 
areas. 
West of Hersey Street the strata are sharply flexed to the 
north, and then resume their normal east-west strike in a group 
of ledges which show a large body of melaphyr above the conglom- 
erate series. The section at this point, as the map shows, overlaps 
and supplements that on Hersey Street, the two together afford- 
ing a nearly complete section of the conglomerate series. The 
contact between the melaphyr and conglomerate is clearly ex- 
posed both east and west of the railroad, and strongly supports 
the view that the melaphyr is contemporaneous. It is plain that 
the conglomerate, although now underlying the melaphyr, was 
deposited over it, for it fills cracks in the melaphyr and is partly 
composed of debris derived from that rock. The conglomerate 
south of the melaphyr, near Hockley Lane, appears to rest in an 
approximately horizontal position and unconformably upon an un- 
even surface of granite, with bosses of granite projecting through 
