This was an earth style cavalier built on the north face of the Bastion. Prior to 1859 it was armed with 9 x 32 lbs. Much of the original cavalier has now been built over but remains of the earthen ramparts can be still be seen.
The map is from the National Archives and shows the Cavalier to have 9 guns, while the lower bastion has 20 guns. Copyright of this map lies with the National Archives.
The Battery Book from the first decade of the 20th Century, about 1910, show that this cavalier was used for a battery of four 6-inch Breech Loading HOwitzers of 30 CWT, Mark I. The were apparently placed on platforms and were able to be moved to other postions. Also referred to as Number 2 Battery (Movable Armaments).
The plan below is from the National Archives, Copyright The National Archives WO 192/12
The photograph is from 1877. This shows the cavalier which is an earthen rampart to protect the guns behind. It would appear there is a guard house in the centre and then access to the casemated batteries on the West front.