Dave, I played about with your example. Very interesting.
The point is clear now. Thank you,
Adrian.

using System;
public class SamplesArray
{
public static void Main()
{
 Type arrayType = Type.GetType("System.String");
 new SamplesArray().DoStuff(arrayType);
}

//public void DoStuff(Type arrayType)
public void DoStuff(Type arrayType)
{
 // Here, Int32 is hard-coded
 int[] intArray = null;

 // Here, an Array of an unknown Type is created (late-bound)
 Array unknownTypeArray = Array.CreateInstance(arrayType,5, 10);

 // if we knew that arrayType was, for example, typeof(int)
 // then we could cast our Array into an int[]:
 if (unknownTypeArray is int[])
 {
  intArray = (int[]) unknownTypeArray;

  Console.WriteLine("int[] length: " + intArray.Length);
  Console.Read();
 }
 else
 {
  Console.WriteLine("unknown Array Type: " +
unknownTypeArray.GetType().FullName);
  Console.Read();
 }
}
}