493bbc30__Touch_Gesture_Reference_Guide__Platform_Description
[Platform] iPhone OS [Platform Gesture] Two-finger scroll [Core Gesture] Drag (Two-finger) [Platform Description] 
A user gesture used to scroll content in an element with overflow capability or a scrollable inline frame element. A two-finger scroll is a drag performed with two fingers moving together in the same direction.
LukeW | Touch Gesture Reference Guide
Platform Description