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Mollet... No.9 
NORTH SHORE BREEZE 
AWWEEKLY- JOURNAL DEVOTED-TO-THE BEST: INTERESTS-OF THENORTHSHDORE 
BEVERLY, MASS., SATURDAY, JULY 16, 1904 
Three Cents 
Entered as second-class matter May 23, 1904, at the post-office at Beverly, Mass., under the Act of Congress of March 3, 1879. 
A GEOLOGICAL RAMBLE 
ON THE NORTH SHORE. 
Weathering of the Shore Line. 
Because of the metamorphosis 
which New England has passed 
through, the rocks, so abundant 
everywhere, reveal little or nothing of 
the former conditions of life—how 
flourished the Mesozoic vegetation, 
what animals left their footprints 
upon the rising and sinking marshes 
and sought shelter in its forest of 
palms, conifers and gigantic ferns. 
But these same upheavals and 
changes of temperature which ob- 
literated most of New England’s fos- 
sils and destroyed, or to a great 
degree prevented, the perfect crystal- 
lization of many mineral bodies, dis- 
tributing them in small and widely 
scattered masses through the gneiss 
and shale, left a record of their acts 
deeply graven in the strata which 
they so completely transformed. In 
New England are found many im- 
portant paragraphs and miscellaneous 
notes which add greatly to the story 
of our planet. 
Almost anywhere may be seen 
some traces of the glacier, either a 
moraine or a striated ledge, a terrace 
or a diluvial deposit, strikes, dips and 
in many localities eruptive torma- 
tions. 
The coast in Essex county is es- 
pecially rich in trap dykes, and some 
of them may be followed for miles. 
The well-defined strata of Gloucester, 
Magnolia and Manchester dipping 
eastward tel] the story of mighty con- 
vulsions in zons past. What a pity 
that they areall of granite, that meta- 
morphosis was carried so far as to ob- 
literate all fossils and leave much in 
doubt as to the exact formative period 
of those massive, weather-beaten 
headlands. Time, tide and chemical 
action are producing changes slowly, 
but none the less surely and the en- 
tire coast line is being changed, pow- 
dered by the tide, and the flinty par- 
ticles thus made are driven hither 
thither by the wind, thus aiding in 
the work of demolition. 
The trap dykes suffer most by rea- 
son of their peculiar composition. Al- 
though much harder than the granite 
around. them, 
—) Bine SUbpHuric 
® acid formed by 
_ decomposition 
in turn decom- 
poses certain 
constituents of 
the mass, and 
this powerful, 
corrosive agent 
combined with 
weathering, dis- 
integration and 
the action of 
frost, breaks up 
the mass_ into 
small cubes or 
large rectangu- 
Jar blocks, which 
the tide readily 
removes or pul- 
verizes. 
Dyke Structures in Process of Removal by Weathering 
CARD 
CATALOGUED, 
Matrix of Dyke in Syenite 
Thus all along the coast large fis- 
sures extend from the sea into the 
headlands into which the tides rush 
in a boiling, seething volume, making 
a dull, heavy boom which echoes 
among the cliffs and wooded shores. 
Rafe’s Chasm at Magnolia, the Brass 
Kettle at the eastern end ot Dana’s 
Beach and the well-known Churn at 
Marblehead are illustraticns of inden- 
tures made by the sea in removing 
dykes from the more durable granite. 
At Magnolia is the most interest- 
ing dyke, which follows the shore for 
nearly half a mile, and then strikes 
into the ocean in the direction of 
Baker’s Island. The strike is due 
east and west, and it has a dip to the 
north of twenty degrees; it is chiefly 
porphyritic and is exposed at half 
tide. The most interesting feature 
of this vein is the series of faults, 
there. being no less than seyen of 
them in sight and probably more_be- 
neath the .sea. In.three places the 
dyke has been shoved squarely to one 
side three feet ; in some places the 
fault equals the width of the dyke, 
and in others it is a foot orless. The 
faults are all in the same direction, 
showing that the pressure was ap- 
