![Avalonia](images/paleomap_Camb.jpg)
It began when an arc of volcanoes ruptured the floor of the ancient Iapetus Ocean south of Gondwana, where the continents of Africa and South America lay interlocked. The seabed explosions unleashed a cataclysm of lava and white-hot rocks. An island chain dubbed Avalonia rose at 60 degrees S. on a platform of volcanic rocks and granite.
Plate Tectonics
![Taconic and Avolonian arcs impact with Laurentia (proto North America)](images/430NAt_taconic_avalonian1.jpg)
In tandem with the drifting continents, Avalonia moved north-north-west across the face of the earth. The archipelago converged with the landmass of Baltica carrying the bedrock of Western Europe. Four hundred million years ago, Avalonia and Baltica collided with Laurentia, the cradle of North America.
The Taconic and Acadian Orogenies
![North American Ice Sheet](images/NorthAmericanIceSheet.jpg)
The ice sheet was the last and most recent glaciation of North America during two-and-a-half million years of the Pleistocene epoch. The big freeze reached from the Pacific to the Atlantic and flowed southward to 40 degrees N. blanketing the northern half of the continent.
Ice Age
![Stellwagen Bank](images/StellwagenBank.jpg)
A glacial great lake occupied Cape Cod Bay, its surface eighty to fifty feet above present sea level, dropping and draining away completely as the Cape Cod Bay lobe moved north. The lobe's meltwater streamed into the outwash that built the Lower Cape. Stellwagen Bank rose north of the Cape, standing as high and dry as the sandy hook six miles away.
Stellwagen Bank
![Boston Neck](images/584px-BostonNeck.jpg)
The sea left Boston peninsula joined to the main by a narrow neck. Coves and creeks indented the seaward shores. Mudflats and saltmarshes reached deep into the sweeping embayment west of the Neck. The tides pushed the high waters into the back bay streaming over the flats and mixing with the flow of the Charles River.
Boston Neck
![Boston Fish Weir, Boylston Street](images/BostonSiteofAncientFishweir.jpg)
Five thousand years ago, the most enterprising member of a small number of hunter-gatherers climbed the highest of the three peaks. The man's eye locked on a myriad school of shad as it rounded the point of the peninsula.
Fish Weir
![Boston 1667](images/AncientBoston1667.gif)
The first name given to the peninsula was Sha-um-ut. No one knows the precise meaning of this ancient place name, which may have been, "Near the Neck," "At the Canoe Landing Place," "By the Living Waters." All had relevance to the people living there for so long.
Boston Harbor 1667
©2015 Errol Lincoln Uys |