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50
50 Beechers 1893 drawing
of Triarthrus, annotated to
show basic trilobite
morphology. Whole animal is
about 3 cm 1.2 in long
excluding antennae.
Diagrammatic appendages
shown at right are from
thoracic segments 2 and 3
from another specimen; note
the two branches: upper, leg
branch endopodite and
lower, gill branch exopodite.
The appendage labelled II has
the setae removed from the
gill branch; that labelled III
shows all setae. Legs are
shown at a magnification of
4
antenna
glabella
cephalon
eye on
palpebral lobe
thorax
pygidium
the size of the whole
trilobite.
×
pleural
lobe
axial
lobe
pleural
lobe
Beecher's quarry. Walcott removed 365
cubic yards of shale in 6 days, and took
the trilobites back to Washington DC
(Whiteley, 1998); meanwhile, Beecher had
been collecting material for the Yale
Peabody Museum (
49
).
Charles Emerson Beecher was the first
invertebrate paleontologist at Yale and was
appointed Curator and Professor of
Geology in 1891. He developed one of
the earliest classifications for trilobites and
brachiopods. During his tenure at Yale, he
published a number of short descriptions
of the remarkable
Triar thrus
trilobites
with appendages (Beecher, 1893a, b,
1895a, 1896), and it was Beecher's
reconstruction of
Triarthrus
showing its
appendages (
50
) that was reproduced in
hundreds of textbooks and other
publications and brought fame to the
finds from Rome. Beecher prepared the
trilobites by rubbing away the soft shale
from the pyritized legs and antennae with
soft erasers. On his untimely death in
1904, Beecher left many specimens,
drawings, and an unfinished monograph
on the anatomy and relationships of
trilobites. One of his former students,
Percy Raymond, became professor at
Harvard University and completed the
monograph which was published in 1920
(Raymond, 1920).
Beecher believed the trilobite quarry to
be worked out, but an attempt was made to
find it by John L Cisne in 1969, when he was
a student at Yale. He found a badly slumped
river bank but did not locate any trilobite
specimens. He concluded that this may
have been the site but that Beecher might
indeed have quarried out the localized
trilobite bed. Cisne (1973a) produced a
detailed palaeoecological study of the
trilobite bed based on museum collections.
Later, when at Chicago University, Cisne
went on to study Beecher's trilobites using
X-rays (Cisne, 1975, 1981).
The bed was eventually rediscovered by
the meticulous studying of old
photographs and published records and
careful searching of the creek by Tom
Whiteley and Dan Cooper, two
industrious fossil collectors, in 1984.
Whiteley contacted the landowner, a most
helpful local farmer, who brought in a
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