diff --git a/README.rst b/README.rst
index dd77116..f3f23b9 100644
--- a/README.rst
+++ b/README.rst
@@ -92,10 +92,10 @@ biome-accurate tinting, the Overviewer can use biome data produced by the
 Minecraft Biome Extractor tool.  This tool can be downloaded from:
 http://www.minecraftforum.net/viewtopic.php?f=25&t=80902
 
-If the EXTRACTEDBIOMES folder is present in the world directory, then the
-Overviewer will use the biome data to tint grass and leaves automatically -- 
-there is no command line option to turn this feature on.  If this folder does
-not exist, then the Overviewer will use a static tinting for grass and leaves.
+If the "biomes" folder is present in the world directory, then the Overviewer
+will use the biome data to tint grass and leaves automatically -- there is no
+command line option to turn this feature on.  If this folder does not exist,
+then the Overviewer will use a static tinting for grass and leaves.
 
 Compiling the C Extension (optional)
 ------------------------------------ 
diff --git a/chunk.py b/chunk.py
index eeef14b..0a7e372 100644
--- a/chunk.py
+++ b/chunk.py
@@ -675,9 +675,9 @@ class ChunkRenderer(object):
         if self.world.useBiomeData:
             biomeColorData = textures.getBiomeData(self.world.worlddir,
                 self.chunkX, self.chunkY)
-        # in the 8x8 block of biome data, what chunk is this?l
-        startX = (self.chunkX - int(math.floor(self.chunkX/8)*8))
-        startY = (self.chunkY - int(math.floor(self.chunkY/8)*8))
+        # in the 32x32 block of biome data, what chunk is this?l
+        startX = self.chunkX % 32
+        startY = self.chunkY % 32
 
         # Each block is 24x24
         # The next block on the X axis adds 12px to x and subtracts 6px from y in the image
@@ -717,14 +717,17 @@ class ChunkRenderer(object):
                 continue
             
             if self.world.useBiomeData:
+                # 16 : number of blocks in a chunk (in one direction)
+                # 32 : number of chunks in a region (and biome file) in one direction
+                # so 16 * 32 == 512 : number of blocks in biome file, in one direction
                 if blockid == 2: #grass
-                    index = biomeColorData[ ((startY*16)+y) * 128 + (startX*16) + x]
+                    index = biomeColorData[ ((startY*16)+y) * 512 + (startX*16) + x]
                     c = textures.grasscolor[index]
 
                     # only tint the top texture
                     t = textures.prepareGrassTexture(c)
                 elif blockid == 18: # leaves
-                    index = biomeColorData[ ((startY*16)+y) * 128 + (startX*16) + x]
+                    index = biomeColorData[ ((startY*16)+y) * 512 + (startX*16) + x]
                     c = textures.foliagecolor[index]
                     
                     t = textures.prepareLeafTexture(c)
diff --git a/gmap.py b/gmap.py
index 2cf6d63..9d6e434 100755
--- a/gmap.py
+++ b/gmap.py
@@ -139,7 +139,7 @@ def main():
     if not composite.extension_alpha_over:
         logging.info("Notice: alpha_over extension not found; using default PIL paste()")
     
-    useBiomeData = os.path.exists(os.path.join(worlddir, 'EXTRACTEDBIOMES'))
+    useBiomeData = os.path.exists(os.path.join(worlddir, 'biomes'))
     if not useBiomeData:
         logging.info("Notice: Not using biome data for tinting")
 
diff --git a/textures.py b/textures.py
index 2478260..da6b35e 100644
--- a/textures.py
+++ b/textures.py
@@ -283,7 +283,7 @@ def _build_blockimages():
        #       48  49  50  51  52  53  54  55  56  57  58  59  60  61  62  63
                36, 37, 80, -1, 65,  4, 25, -1, 98, 24, 43, -1, 86, -1, -1, -1, # Torch from above? leaving out fire. Redstone wire? Crops/furnaces handled elsewhere. sign post
        #       64  65  66  67  68  69  70  71  72  73  74  75  76  77  78  79
-               -1, -1, -1, 16, -1, -1, -1, -1, -1, 51, 51, -1, -1,  1, 66, 67, # door,ladder left out. Minecart rail orientation
+               -1, -1, -1, 16, -1, -1, -1, -1, -1, 51, 51, -1, -1, -1, 66, 67, # door,ladder left out. Minecart rail orientation
        #       80  81  82  83  84  85  86  87  88  89  90  91
                66, 69, 72, 73, 74, -1,102,103,104,105,-1, 102 # clay?
         ]
@@ -300,7 +300,7 @@ def _build_blockimages():
        #        48  49  50  51  52  53  54  55  56  57  58  59  60  61  62  63
                 36, 37, 80, -1, 65,  4, 25,101, 98, 24, 43, -1, 86, -1, -1, -1,
        #        64  65  66  67  68  69  70  71  72  73  74  75  76  77  78  79
-                -1, -1, -1, 16, -1, -1, -1, -1, -1, 51, 51, -1, -1,  1, 66, 67,
+                -1, -1, -1, 16, -1, -1, -1, -1, -1, 51, 51, -1, -1, -1, 66, 67,
        #        80  81  82  83  84  85  86  87  88  89  90  91
                 66, 69, 72, 73, 74,-1 ,118,103,104,105, -1, 118
         ]
@@ -824,9 +824,9 @@ def prepareBiomeData(worlddir):
     if grasscolor and foliagecolor:
         return
     
-    biomeDir = os.path.join(worlddir, "EXTRACTEDBIOMES")
+    biomeDir = os.path.join(worlddir, "biomes")
     if not os.path.exists(biomeDir):
-        raise Exception("EXTRACTEDBIOMES not found")
+        raise Exception("biomes not found")
 
     # try to find the biome color images.  If _find_file can't locate them
     # then try looking in the EXTRACTEDBIOMES folder
@@ -850,16 +850,13 @@ def getBiomeData(worlddir, chunkX, chunkY):
 
     global currentBiomeFile, currentBiomeData
 
-    biomeFile = "%d.%d.biome" % (
-        int(math.floor(chunkX/8)*8),
-        int(math.floor(chunkY/8)*8)
-            )
+    biomeFile = "b.%d.%d.biome" % (chunkX // 32, chunkY // 32)
     if biomeFile == currentBiomeFile:
         return currentBiomeData
 
     currentBiomeFile = biomeFile
 
-    f = open(os.path.join(worlddir, "EXTRACTEDBIOMES", biomeFile), "rb")
+    f = open(os.path.join(worlddir, "biomes", biomeFile), "rb")
     rawdata = f.read()
     f.close()