 In the early 4th millennium BC the track was built between an island at Westhay , and a ridge of high ground at Shapwick close to the River Brue . A group of mounds at Westhay mark the site of pre @-@ historic lake dwellings , which were likely to have been similar to those found in the iron age Glastonbury Lake Village near Godney , itself built on a morass on an artificial foundation of timber filled with brushwood , bracken , rubble and clay . 
