Section 3. in the City of Boston No Building Shall Be Erected to a

height of more than one hundred and twenty-five feet above the grade of the street in any district designated A, and no building shall be erected to a height of more than eighty feet above the grade of the street in any district designated B. These restrictions shall not apply to grain or coal elevators or sugar refineries in any district designated A, nor to steeples, domes, towers or cupolas erected for strictly ornamental purposes, of fireproof material, on buildings of the above height or less in any district.

The supreme judicial court and the superior court shall each have jurisdiction in equity to enforce the provisions of this act, and to restrain the violation thereof.