SortedList Descending

Hello everybody,
I am pretty sure that recently I declared a SortedList with descending order, it could look like

SortedList<int, int> sl = new SortedList<int, int>().OrderByDescending

but clearly that does not work.
The best I am now able to do is to declare the SortedList with nothing specified about the order, and then after initializing it :
IEnumerable lst = sl.OrderByDescending(v => v.Value);
and that works jolly good, but of course that way I use more memory as I double the list.

Does anyone see how I could do it the other day ?