wherever I have seen the _asclepias tuberosa_, I have always
remarked, too, on the flower a large butterfly, so nearly resembling it in
color as to be distinguishable at a little distance only by the motion of
its wings. Traveling on, the fresh traces of the Oregon emigrants relieve
a little the loneliness of the road; and to-night, after a march of
twenty-two miles, we halted on a small creek which had been one of their
encampments. As we advanced westward, the soil appears to be getting more
sandy; and the surface rock, an erratic deposite of sand and gravel, rests
here on a bed of coarse yellow and gray and very friable sandstone.
Evening closed over with rain and its usual attendant hordes of
mosquitoes, with which we were annoyed for the first time.

22d.--We enjoyed at breakfast this morning a luxury, very unusual in this
country, in a cup of excellent coffee, with cream, from our cow. Being
milked at night, cream was thus had in the morning. Our mid-day halt was
at Wyeth's creek, in the bed of which were numerous boulders of dark,
ferruginous sandstone, mingled with others of the red sandstone already
mentioned. Here a pack of cards, lying loose on the grass, marked an
encampment of our Oregon emigrants; and it was at the close of the day
when we made our bivouac in the midst of some well-timbered ravines near
the Little Blue, twenty-four miles from our camp of the preceding night.
Crossing the next morning a number of handsome creeks, with water clear
and sandy beds we reached, at 10 A.M., a very beautiful wooded stream,
about thirty-five feet wide, called Sandy creek, and sometimes, as the
Ottoes frequently winter there, the Otto fork. The country has become very
sandy, and the plants less varied and abundant, with the exception of the
_amorpha_, which rivals the grass in quantity, though not so forward
as it has been found to the eastward.

At the Big Trees, where we had intended to noon, no water was to be found.