diff --git a/tsk/fs/tsk_fs.h b/tsk/fs/tsk_fs.h
index 1921ef79b56c3c4482bde997650d4df713090fd0..2158584563104b5158975835cc73a11ccfdf243b 100644
--- a/tsk/fs/tsk_fs.h
+++ b/tsk/fs/tsk_fs.h
@@ -780,7 +780,15 @@ extern "C" {
 
     /**
     * Values for the file system type.  Each bit corresponds to a file
-    * system.
+    * system. The "[fs]_DETECT" value (such as TSK_FS_TYPE_NTSF_DETECT) is 
+    * the OR of all of the subtypes that 
+    * it could detect.  If there is only one type of that file system, 
+    * the [fs]_DETECT value will be the same as the type. 
+    *
+    * The _DETECT values should not be stored in TSK_FS_INFO.  Once 
+    * tsk_fs_open() has detected the type, it should assign the specific
+    * version in TSK_FS_INFO.
+    *
     */
     enum TSK_FS_TYPE_ENUM {
         TSK_FS_TYPE_DETECT = 0x00000000,        ///< Use autodetection methods