Removed MySQL (unsupported) from Perimeter docs.
@@ -409,9 +409,7 @@ On MySQL, returns ``None`` for any non-``LINESTRING`` geometry.
Oracle, SpatiaLite
Accepts a single geographic field or expression and returns the perimeter of the
-geometry field as a :class:`~django.contrib.gis.measure.Distance` object. On
-MySQL, a raw float value is returned, as it's not possible to automatically
-determine the unit of the field.
+geometry field as a :class:`~django.contrib.gis.measure.Distance` object.
``PointOnSurface``
==================
