Yellowstone National Park - Yellowstone and Grand Teton National Parks - page 160

Nearby Turban Geyser acts as a trigger for Grand and, along with Vent Geyser , contin-
ues to rage for one to two hours after Grand subsides.
Sawmill Geyser is in eruption about 30% of the time, but its extents are highly vari-
able. Water spins violently in its crater like a circular saw. Nearby Spasmodic is also in
eruption a third of the time and erupts from more than 20 vents.
Rangers lead 90-minute walks of the Upper Geyser Basin daily at 5:30pm.
BLACK SAND BASIN
This geyser basin, 1 mile northwest of Old Faithful, has a few interesting features. The
eponymous black sand is derived from weathered volcanic glass (obsidian). You can ac-
cess Black Sand Basin by car or, better, by foot from Daisy Geyser. Rangers lead hour-
long walks here daily at 1pm.
Cliff Geyser is named for the geyserite wall that separates the geyser from Iron Spring
Creek and is a frequent splasher. Nearby Ragged Spring frequently joins in the action
with 12ft bursts. Emerald Pool looks like an exquisite flower with a lovely orange lip and
gets its pretty color from yellow bacteria that blend with blue reflected from the sky.
Rainbow Pool is connected to nearby Sunset Lake and is one of the more colorful in the
park. The ground under the boardwalks here is literally boiling.
Unsigned Handkerchief Pool , just to the south of Rainbow Pool, was once one of Yel-
lowstone's most famous features. Visitors would place a handkerchief in the pool and
watch it get sucked down and then spat out 'clean' through a side vent. The pool stopped
functioning in the 1920s, after one dimwit jammed logs into the opening, but it has since
restored itself. Today it's illegal to throw anything into any of Yellowstone's thermal fea-
tures.
BISCUIT BASIN
Two miles further north, Biscuit Basin was named for biscuitlike deposits that surrounded
stunning Sapphire Pool , but these were destroyed during violent eruptions that followed
the nearby 1959 Hebgen earthquake. If you're low on time, this is one basin you could
safely miss.
The main features here are deep Jewel Geyser , which erupts every 10 minutes or so,
with lovely yellow run-offs, and Shell Geyser , which is shaped like a clamshell and
linked underground. Mustard Spring is named for its iron oxide-induced dark-yellow
color.
A 0.5-mile hiking and biking trail leads from across the highway to Upper Geyser Bas-
in's Daisy Geyser and a hiking-only path crosses the road to lead to Artemisia and Atom-
izer geysers in the Upper Geyser Basin.