List<>[.] 2 Dimensional Array?

Question

Currently I'm using this code:

    List<Numbers>[] numbers = Enumerable.Range(1, 4500000).Select(n => new List<Numbers>()).ToArray();

Now I need to make it

    List<Numbers>[,] = what do I do here,  it'll be [39,enumerable.range]

if possible?

thanks for any help