This document provides an overview of the evolution of aggregate supply to Boston, Massachusetts. It discusses how Boston was originally developed on glacial sand and gravel deposits starting in the 1860s. Aggregate sources then expanded through the development of vertically integrated quarries and the excavation of pits into ledge rock. Transportation infrastructure like railroads, trucks, barges, and the interstate system helped aggregate be transported into Boston from farther locations. The document gives details on the geology and specific rock types supplying quarries around Boston, and provides a counter-clockwise tour of various quarry locations, rock types, and years of operation. It concludes with contact information for the presentation author.