I am not really sure what you are trying to achieve here, but to get the type of the elements in an array, you have to use Type.GetElementType()
:
void SomeFunction<T>()
{
var type = typeof(T);
if(type.IsArray)
{
var elementType = type.GetElementType();
var method = typeof(Foo).GetMethod("SomeOtherFunction")
.MakeGenericMethod(elementType);
// invoke method
}
else
foo.SomeOtherFunction<T>(...);
}