1) It was not unusual formerly for rainwater to be drained from a town street via a channel that ran between the pavement and the entrances to the houses. The stone across the channel was called a bridge-stone.
The OED has the word from 1876 but examples occur in Yorkshire from the 1600s and it will have a much longer history: 1639 that ... Edward Langfield and William Beatson do scoure their ditches in Back laine and brynge yt vnder the Brigstone before William Beasons dore, Ossett. At the Almondbury court in 1690, Widow Akersley was ordered to permit the water that runns under the Brigg stone before Thomas Beaumont’s dore in Huddersfield to pass through the ancient course. Some bridge-stones of this kind survive in small towns like Settle.Alternatively, a single stone which crossed a narrow stream could be referred to as a bridge-stone and this term survived as a minor place-name in Lothersdale. It was also the probable origin of bridgestone in a Pudsey document of 1629. Similar examples occurred in Tong: 1684 the causey adioyneing upon the brigstone at Bentham Syke and in Northowram, where two workmen were ordered to lay a sufficient brigg-stone over the water-course running at the bottom of New Brigg Lane.Not surprisingly, it is a word found frequently in descriptions of boundaries. In 1667, one point on the perambulation of Tong boundary was the Bridgestone in the High streete divideing betweene Tonge and Bolling. In 1759 the Shelley perambulation began at a Brigstone dividing the manor from that of Skelmanthorpe.. An interesting order at the Quarter Sessions in 1714 required certain Bridge Stones and rails … to be erected in crofts … at Apperley Bridge for Travelleres … to pass through when the River overflowed the road.More literally the word was used of the stones used to build a bridge. These were valuable items and would be recovered whenever possible after a bridge had collapsed. It was the masons’ task to retrieve them, and they are often referred to in accounts in the Quarter Sessions Rolls. In 1675, when Ilkley Bridge was reconstructed, one entry was for getting the Old Bridge Stones out of the River : in 1697, the builder at Long Preston was paid for his time seekeing of Stoans in the Water . The earliest reference I have noted to this practice is in the Kirkstall Bridge contract: 1619 John Phillip do acknowledge to have received ... twentie two poundes for the working of stones ... and for getting of stones oute of the water there.