Giant White Thistle?

Afternoon all!

I've been trying to identify this on my own, with no luck. It is a HUGE thistle-like plant, and the bottom is growing outward in a rather interesting circular pattern. Would appreciate any help with identification! OH, and in case you're wondering how large it really is, that shadow on the bottom of the picture is my head! :)

 

yellow thistle, bull thistle, Cirsium horridulum var. horridulum
was called Carduus spinossissimus

 

Thank you! I think we have some that have broken some kind of record...they're well over 4 feet tall. Well, you know what they say...everything is bigger in Texas! :)