diff --git a/Newly-Identified-Fields.md b/Newly-Identified-Fields.md
index 88645ee..29676ad 100644
--- a/Newly-Identified-Fields.md
+++ b/Newly-Identified-Fields.md
@@ -11,4 +11,6 @@ The following is a list of fields and addresses whose meaning has been identifie
 
 dword_1358830 seems to store the upper boundary of the map? sub_68B93A checks whether coordinates ax and cx are on or off of the map and errors if they are.
 
-game flag 0x20h is a check for the tree height. 68b9b7 checks for this, and if so, rides can't be taller than 0x12 units, of something.
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+game flag 0x20h is a check for the tree height. 68b9b7 checks for this, and if so, rides can't be taller than 0x12 units, of something.
+
+0x0138B616 is a store for `i`, which increments from 0 to MAX_RIDES in the update_ride_measurements function. i is stored and then retrieved after some work is done in that register
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