. History of the town of Hingham, Massachusetts . to its designation as amyg-daloid. Indeed a large portion of the melaphyr of Rocky Neck isfinely amygdaloidal, and affords good specimens of this variety ofthe rock. On the beach here there is a protruding flat surfaceof rock, a yard or so in diameter, on which may be seen glacial The Geology of HIngham. 49 striae, though probably exposed there to the elements for centu-ries. These lines are northwest and southeast, and south 30°east. Other lines on a neighboring rock are northwest by westand southeast by east. On the westerly side of the bay g
. History of the town of Hingham, Massachusetts . to its designation as amyg-daloid. Indeed a large portion of the melaphyr of Rocky Neck isfinely amygdaloidal, and affords good specimens of this variety ofthe rock. On the beach here there is a protruding flat surfaceof rock, a yard or so in diameter, on which may be seen glacial The Geology of HIngham. 49 striae, though probably exposed there to the elements for centu-ries. These lines are northwest and southeast, and south 30°east. Other lines on a neighboring rock are northwest by westand southeast by east. On the westerly side of the bay graniteappears in a high cliff towards and extending into the water. By ascending this cliff, passing over it to its western declivityand descending to the narrow beach at its base, which should bedone at low tide, a dike exposure may be seen of much is what is called a double dike, the molten material havingmade its way to the surface within two contiguous joints in thegranite. The larger portion has a width of about eight feet, the. Figure No 3. smaller one about one foot, and they are separated by about one footof the invaded rock. See Figure No. 3. This double dike slopesto the south from the vertical at an angle of 45°. This is theextreme western end, on Rocky Neck, of the dike first mentionedas appearing on the eastern shore. It does not present there VOL. I. 50 History of Hingha/m. or generally over the surface of the neck its double character be-cause obscured by the soil. Across the water of the river, onNantasket where it reappears, it shows itself double. THE GLACIAL PERIOD. A pretty full notice of the great glacier that rested over theNorth, and the phenomena attendant upon its advance andfinal melting away, has been given in the preliminary have now only to treat particularly of the traces left uponthe surface of the town by its passage. Those who bave atten-tively read what has been expressed will understand that thedecomposed material of e
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