Re: Equids

Phillip Bigelow (
Wed, 14 Dec 1994 19:28:24 GMT

jdolan@math.UCR.EDU (james dolan) writes:

> (whittet) writes:
>->If the North American equus c., reputedly able to maintain itself
>->in one form or another in the Americas for 60 million years,
well, not quite: there is strong evidence for an extinction event in
North America circa 10,000 ybp.

>James dolan writes:
>ok, then 59,990,000 years.

well, not quite: If we use the earliest dates for the emergence of the
family Equidae, then the temporal range would be from 25 million years
to 10,000 years. In geological terms, it is customary to round off
units within the limits of radiometric dating accuracy; so the magic
number is more like 25 million years, give or take five humdred
thousand or so.
If we use the emergence of Hyracotherium (a proto-horse), then the
magic number is closer to fifty million years.