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Re: W. D. Matthew's _Dinosaurs_

> On 7/14/07, Michael Mortimer <mickey_mortimer111@msn.com> wrote:
>> Ah, the Comanchic and Eogene periods.  And the KT event only 3.1 Mya.  I
>> didn't realize such things were believed in 1915.
> A web search for "Eogene" turns up papers as late as the '30s.
> I've never heard of these before, and can't seem to find a history of
> either term on the web. Are these older names for certain units (Early
> Cretaceous, Paleocene) or do they reflect erroneous ideas about
> correlated strata?

The former. Some authors were still using "Comanchean" in the mid-20th
century, and the USGS (among others) were very late to formerly recognize
the Paleocene.

As for the dating scheme: the AMNH (and Osborn and particular) were rather
notoroious for their late adoption of radiometric dating schemes, and
stuck with Kelvin timescales. (In part this may have been related to
Osborn's rejection of natural selection for his own aristogenesis model of
evolution, with wouldn't require as long time scales).

But to be fair, it really wasn't until Arthur Holmes work in the 1930s
that a serious geochronologic scale was developed.

Well, off to the Great White North (for wine, not bones...)

                Thomas R. Holtz, Jr.
        Senior Lecturer, Vertebrate Paleontology
Department of Geology           Director, Earth, Life & Time Program
University of Maryland          College Park Scholars
        Mailing Address:
                Building 237, Room 1117
                College Park, MD  20742

Phone:  301-405-4084    Email:  tholtz@geol.umd.edu
Fax (Geol):  301-314-9661       Fax (CPS-ELT): 301-405-0796