History Of the Cushing Formation

Quaternary Period

Glaciers Disappear from Maine

28,000 B.C. - 10,000 B.C.

Jurassic Period

Basalt Dikes Intrude into Bedrock

200,000,000 B.C. - 190,000,000 B.C.

Basalt dikes intrude into bedrock on Maines Coast

Opening of the Atlantic Ocean

200,000,000 B.C.

Permian Period

Final Assembly of Pangea

280,000,000 B.C.

Coast of Maine Fully Formed

250,000,000 B.C.

Carboniferous Period

Metamorphic Gneiss Formed

350,000,000 B.C.

Devonian Period

Acadian Orogeny

405,000,000 B.C. - 365,000,000 B.C.

Formation of most granites in Maine

Acadian Mountains Formed

400,000,000 B.C. - 360,000,000 B.C.

Ordovician Period

Early Fish

490,000,000 B.C.

Taconic Orogeny

471,000,000 B.C.

Many minerals formed

Present Day

Portland Head Light Constructed

1791