diff --git a/GPX.cabal b/GPX.cabal
--- a/GPX.cabal
+++ b/GPX.cabal
@@ -1,5 +1,5 @@
 Name:                GPX
-Version:             0.6.1
+Version:             0.6.2
 License:             BSD3
 License-File:        LICENSE
 Synopsis:            Parse GPX files
diff --git a/src/Data/Geo/GPX/Extensions.hs b/src/Data/Geo/GPX/Extensions.hs
--- a/src/Data/Geo/GPX/Extensions.hs
+++ b/src/Data/Geo/GPX/Extensions.hs
@@ -8,22 +8,22 @@
 import Text.XML.HXT.Arrow.Pickle
 import Text.XML.HXT.DOM.TypeDefs
 
-newtype Extensions = Extensions XmlTree
+newtype Extensions = Extensions XmlTrees
   deriving Eq
 
 extensions :: 
-  XmlTree
+  XmlTrees
   -> Extensions
 extensions =
   Extensions
 
 runExtensions ::
   Extensions
-  -> XmlTree
+  -> XmlTrees
 runExtensions (Extensions t) =
   t
 
 instance XmlPickler Extensions where
   xpickle =
-    xpWrap (Extensions, \(Extensions t) -> t) xpTree
+    xpWrap (Extensions, \(Extensions t) -> t) xpTrees