This bonus geocache is NOT at the posted coordinates.
First, you will need to install the "Adventure Lab" app available from the app store on your smart phone (Android or IOS).
The adventure lab listing can be found at the following URL https://adventurelab.page.link/9qNi on your phone.
You will need to complete the " Historic Boulder Walkabout Part II" Adventure Lab in order to get the final coordinates. You will have 5 locations to visit in any order before you will have the complete co-ordinates for the Bonus cache. You may retrieve the co-ordinates at anytime after you have completed the tour by viewing the journals of the "Historic Boulder Walkabout Part II" Adventure Lab series. Each location will provide you with 2 of the partial co-ordinates.
This Bonus cache can be found at: N40 AC.EGJ W105 BD.FHK
The bonus cache is located along a paved walking/biking path. At times the location can be very busy so stealth is needed!!!! The cache will hold some small swag. There are a couple small pencils in the container but you might want to BYOP.