This drive-by earth cache will display what the land looks like
after an earthquake. Driving the Lewiston grade takes you through
successive flows of basalt. Each flow is 40-50 feet thick and is
delineated by a little grassy slope. These flows occurred during
the Miocene Era, about 15 million years ago. The separate lava
flows were up to several thousand years apart. Occasionally, a
layer of red, oxidized basalt marks a flow top. Note the difference
between the rocky, angular basalt and the grainy red flow top
below. As you travel downhill, this same red layer reappears.
At the listed coordinates, a diagonal line marks a shift of the
earth. This was probably not high drama for the insects roaming the
land about this time. The Clarkia fossil beds east of Moscow
contain many samples of the flora and fauna extant during this
period.
You need not exit your vehicle to claim this cache. As you drive
by, count the number of separate flows of lava atop the red layer.
Calculate the number of centuries required to attain the top of the
hill, figuring about 20,000 years between each flow. Email me the
number of centuries. N.B. The time frame is approximate.
If you wish to get up close to the site, do not park on the
highway shoulder. A sizable pull-out exists a couple hundred yards
beyond the coordinates, either uphill or downhill. If you plan to
CITO the shoulder you could fill a large bag during the short
walk.