Starting at 15 feet ( 4.6 m ) above sea level , The first 3 3⁄4 miles ( 6.0 km ) , through Barnstaple , and along the Yeo Valley stays relatively level .
Starting at 15 feet ( 4.6 m ) above sea level , The first 3 3⁄4 miles ( 6.0 km ) , through Barnstaple , and along the Yeo Valley stays nearly level .