I posted a plan and photo of the first tower on the Portland Breakwater a few days ago. Here is a historic image of the current cast iron tower constructed on the breakwater in 1875. Note that the building attached to the tower no longer exists. And the current tower is now painted white rather than a dark color. Below is a Historic American Building Survey (HABS) drawing of the current tower. Note the classical columns. You can download high-resolution HABS/HAER/HAL drawings and photos from the Built in America section of the Library of Congress website.
Click on images to see a larger view. Like many of the early pier lights, the first tower built on the Portland, Maine, breakwater in 1855 was constructed of wood. It was replaced in 1875 by the current cast iron tower.