 Complete the following phrase:  Unlike other early stations in Boston, which were built with cut-and-cover tunneling, most of Atlantic Avenue station was built as a large barrel vault. Drifts were first used to construct the vertical station walls, then the crown of the arch. Transverse sections of the arch were then completed, followed by the invert. The arch was wide and tall; the walls of the station were thick and the arch thick. Work began on this section on March 17, 1902; the last section of arch was completed on June 26, 1903. The rough work of the station vault was completed on August 28, 1903, with the tilework finished on January 19, 1904, and the granolithic platforms on February 10. The 