1000 The American Naturalist. [December, 
—the carnivora—pursue their prey and drive them into 
lakes or rivers or, perhaps, force them over precipices. Dr. 
Hayden has observed similar occurrences, and in the same 
place where he records this observation corroborates the inter- 
esting suggestion of Lyell as to animals meeting their death 
by falling through thinice. He says: “The wolves watch the 
deer, antelope and other feebler animals as they go down to 
the streams to drink, and all over the wide bottoms are the 
skeletons of these animals in a more or less perfect condition. 
It is not an uncommon occurrence for a band of wolves to at- 
tack an aged buffalo too old to offer a successful resistance. 
He must always betake himself to the river, where he is not 
unfrequently drowned, or is destroyed by the wolves on a sand 
bar or island. Annually thousands of buffaloes are drowned 
in attempting to cross the Missouri on the ice, as it is breaking 
up in the spring. Their bodies have been seen floating down 
the Missouri at Fort Union and Fort Clark by hundreds, and 
lodging on some of the islands or sand bars in the river. In 
the spring of 1858 several thousand bodies of buffaloes passed 
down the Kansas River below the mouth of Solomon’s Fork 
and were carried into the Missouri.” 
Dr. Holub speaks of the devastation amongst oxen, elands, 
hartebeests, sheep, goats, wild pigs, etc., wrought by the at- 
tacks of hyenas in South Africa as “really frightful,” and in 
pliocene times on our globe similar causes may have led to the 
collection of important groups of fossils. Even the instincts 
of animals may lead to their wholesale destruction. Mosely 
speaks of the migration of turtles at Ascension Islands saying, 
“the young turtles on leaving the egg go down to the sea and 
disappear, returning only when full grown to breed; this is 
the account given by the residents. If they do really leave 
the neighborhood of the island, there seems no possible means 
by which they can find their way back.” 
Although it is impossible that any of the fish beds, found as 
fossils, can, at least in paleozoic or mesozoic rocks, have been 
formed in the way instanced by Nordenskiold as a cause of 
death amongst arctic fish, yet the circumstance is intrinsically 
interesting, and the the reflections it suggests as to the likeli- 
