SPRINGTIME ON THE YUKON. 599 
dashes its clear cold water into the muddy Y ukon-tide, offers 
an inviting nook, and into it we haul our bark, and, making 
fast to a projecting willow root, scatter in search of “speci- 
mens.” A tough climb of ten minutes takes us to the top 
of the brown sandstone bluff, broken and weatherworn; yet 
showing, in its successive layers of clayey and sandy rock 
with thin lamine of fossil vegetable matter, that, in ages 
gone by, the same forces were at work there, that we now 
observe on the recent river bank; each series of three layers 
shows how some flood came down and deposited first its 
sand, next its clay in the form of fine mud, and lastly 
any fragments of wood or vegetable matter which the re- 
ceding waters left behind them. In the rocks above, how- 
ever, a different state of things may be observed. Instead 
of the fragments of leaves of sycamores (Platanus), of 
carbonized wood, and of unrecognizable vegetable matter, 
we find remains of fuci, here and there a fragment which 
may have been of terrestrial origin; and, especially, remains 
of mollusca, mostly bivalves, such as oysters, mussels, and 
similar shell-fish, and very rarely a mass of remains which 
may once have been a fish. These fossils, though metamor- 
phosed, broken, crushed, and frequently existing only as 
casts, are sufficient to indicate a miocene age for the rocks 
in which they occur, and no fossils of the older rocks have 
yet been found on the lower Yukon. 
By turning over some of these prostrate trunks we shall 
obtain rare prizes in the shape of Carabide, beetles, fre- 
quently of brilliant colors and large size, of which some are 
so rare that an enthusiastic entomological. friend once ex- 
claimed to us, when parting: “Oh, if I thought I could 
discover the Carabus Vittinghevit, I think I should leave my 
business and go with you!” In the same locations are to be 
found minute land shells (Helix chersina, striatella, electrina 
and others, as well as minute species of Pupilla and Vertigo, 
all common to the northern zone of the world, from Sweden 
to Labrador, though known under various local names. 
