 The Medway long barrows all <unk> to the same general design plan , and are all aligned on an east to west axis . Each had a stone chamber at the eastern end of the mound , and they each probably had a stone facade flanking the entrance . The chambers were constructed from sarsen , a dense , hard , and durable stone that occurs naturally throughout Kent , having formed out of <unk> sand from the <unk> . Early Neolithic builders would have selected blocks from the local area , and then transported them to the site of the monument to be erected . 
