This Cache
The cache should be fairly easy to find. You're looking for a Film Canister, so don't forget a pen or pencil.
About Slartibartfast
From Wikipedia:
Slartibartfast is a Magrathean, and a designer of planets. His favourite part of the job is creating coastlines, the most notable of which are the fjords found on the coast of Norway on planet Earth, for which he won an award.
Congratulations to Eh1414 for the FTF!!