This is a sort of lumpish pile of boulders and rock located just southwest of the Jimmy Cliff area. You're not likely to run into anyone here, other than folks ticking off the list from the "Trad Guide to Joshua Tree"
Getting There
From the parking area for Atlantis or the Jimmy Cliff, hike south on a trail past the Atlantis turnoff, then past Jimmy Cliff, then turn right 90 degrees and walk past the south end of Jimmy Cliff to Grossvogel.