Dragon1
Rear Admiral
The Nevada class, along with many dreadnoughts up to the Tennessee class had the secondary battery built into the main deck and superstructure. These emplacements were essentially an advanced version of a gun port. They were called casemates. The old BBs had a battery of 5"/51 SP weapons for anti-destroyer work and deck mounted 5"/25 DP (single) or 3"/50 DP. All these were later replaced by the standard WWII 5"/38cal DP, some of which were mounted in dual turrets.
Just as a side note, prior to WWII many of the hull mounted casemate guns were removed and filled in. The superstructure 5"/51's remained until later.
In the Pearl Harbor Attack of 7 December 1941, the only significant damage to the USS Pennsylvania (then in drydock) was a bomb that had penetrated the armor of one of the superstructure casemates.
Just as a side note, prior to WWII many of the hull mounted casemate guns were removed and filled in. The superstructure 5"/51's remained until later.
In the Pearl Harbor Attack of 7 December 1941, the only significant damage to the USS Pennsylvania (then in drydock) was a bomb that had penetrated the armor of one of the superstructure casemates.