 A flat @-@ roofed magazine was cut out of the rock just below the blockhouse in the 19th century , and a gun platform with two circular recesses for gun carriage rails was constructed , protected by a granite parapet . The curtain wall was reworked in this period and marked by plaques labelled " WD 1855 " . The recesses and marks from the additional defences in the Second War can still be seen in places along the gun platform . 
