Index: src/clear_cmd.cpp
===================================================================
--- src/clear_cmd.cpp	(revision 27199)
+++ src/clear_cmd.cpp	(working copy)
@@ -112,7 +112,7 @@
 			break;
 
 		case CLEAR_ROCKS:
-			DrawGroundSprite((TileHash(ti->x, ti->y) & 1 ? SPR_FLAT_ROCKY_LAND_2 : SPR_FLAT_ROCKY_LAND_1) + SlopeToSpriteOffset(ti->tileh), PAL_NONE);
+			DrawGroundSprite((HasGrfMiscBit(GMB_SECOND_ROCKY_TILE_SET) && (TileHash(ti->x, ti->y) & 1) ? SPR_FLAT_ROCKY_LAND_2 : SPR_FLAT_ROCKY_LAND_1) + SlopeToSpriteOffset(ti->tileh), PAL_NONE);
 			break;
 
 		case CLEAR_FIELDS:
Index: src/newgrf.h
===================================================================
--- src/newgrf.h	(revision 27199)
+++ src/newgrf.h	(working copy)
@@ -61,6 +61,7 @@
 	GMB_TRAIN_WIDTH_32_PIXELS  = 3, ///< Use 32 pixels per train vehicle in depot gui and vehicle details. Never set in the global variable; @see GRFFile::traininfo_vehicle_width
 	GMB_AMBIENT_SOUND_CALLBACK = 4,
 	GMB_CATENARY_ON_3RD_TRACK  = 5, // Unsupported.
+	GMB_SECOND_ROCKY_TILE_SET  = 6,
 };
 
 enum GrfSpecFeature {