 The earthen mound that once covered the tomb is now visible only as an undulation approximately 1 foot , 6 inches in height . In the nineteenth @-@ century , the mound was higher on the western end of the tomb , although this was removed by excavation to reveal the sarsens beneath during the 1920s . It is likely that in the Early Neolithic , the mound had a quarry ditch surrounding it , and it is inside this ditch that the kerb @-@ stones now sit . 
 The earthen mound <a href='null_relcl' title='1'><mark>that</mark></a>once covered the tomb <a href='drop_aux' title='2'><mark>is</mark></a>now visible only as an undulation approximately 1 foot , 6 inches in height . In the nineteenth @-@ century , the mound was higher on the western end of the tomb , although this was removed by excavation to reveal the sarsens beneath during the 1920s . It is likely that in the Early Neolithic , the mound had a quarry ditch surrounding it , and it is inside this ditch that the kerb @-@ stones now sit . 
Da earthen mound once covered the tomb now visible only as an undulation approximately 1 foot , 6 inches in height . In the nineteenth @-@ century , tdamound was higher on the western end of thdaomb , although this was removed by excavation to reveal thedarsens beneath durin the 1920s . It is likely that in the Early Neolithic , the dand had a quarry ditch surrounding it , and it is inside this ditch dat the kda @-@ stones now sit .