First of all there is no extension to object with the name "
type
"
Here is the LINQ query as close as I can get to what I think you are asking:
var list1 = new List<object>();
list1.Add("Something");
var item = list1.FirstOrDefault(i => i.GetType().ToString() == "System.String");
Console.WriteLine(item.GetType());
Console.ReadLine();