A History of Ideas in Ichnology - Trace Fossils as Indicators of Sedimentary Environments - page 19

Dagestan. Such studies started in the 1930s and significantly deepened the
knowledge of trace fossils, although their exact nature was not always clear.
For instance, Grossheim (1946) noted traces of crawling worms but considered
Paleodictyon as a cast of mudcracks. Thanks to their abundance within the
Carpathian flysch, hieroglyphs were also commonly reported in the Romanian
geological literature. For instance, Mrazec compared hieroglyphs to modern
insect and gastropod traces, pioneering neoichnological studies in Romania.
Interestingly, Filipescu described Paleodictyon as a “burrow system”
( Brustur, 1997 ). Despite these insightful interpretations, throughout the first
half of the twentieth century, the major part of Romanian geologists used the
term fucoid to indicate trace fossils.
A period of stagnation was experienced also on the other side of the world. In
North America, ichnology was viewed as a minor branch of paleontology, and
minor progress was made. Carroll Lane Fenton and his wife Mildred Adams Fen-
ton were paleontologists who turned their careers to popular science writing—and
who, like Dawson and Logan, had seashore experience that enabled them to
propose plausible makers of Paleozoic trace fossils by use of actualistic reason-
ing. For example, they showed that phoronids could make Skolithos linearis
(Supplementary Material: http://booksite.elsevier.com/9780444538130 ). Other
influential studies included those of the Cincinnati-based Kenneth Caster (Devo-
nian limuloid trackways), Lionel Brady (Permian arthropod trackways), and
Benjamin F. Howell ( Skolithos and other early Paleozoic burrows) (Supplemen-
tary Material: http://booksite.elsevier.com/9780444538130 ) . The piecemeal
nature of this work made progress slow; few attempts were made outside Europe
to systematize ichnology at this time. However, the stage was set as the value of
actualistic marine research, especially in Germany, France, and England, became
more broadly appreciated.
In the same period, ichnology started blooming in South America and Asia.
It should be emphasized, however, that these ichnological schools had a
different development under different circumstances than European and North
American ichnology. For this reason, Osgood's (1970, 1975) periodization
serves here only as a chronological reference. South American ichnology went
through a slow start. Trace fossils were only occasionally mentioned, almost
invariably within the context of regional studies. The Uruguayan school teacher
Lucas Rosselli represents an exception, as he accurately documented insect
trace fossils from Paleogene paleosols in Uruguay ( Roselli, 1938 ). These
deposits host the world's most diverse paleosol ichnofauna, and Rosselli's stud-
ies are at the foundation of the present-day school of insect paleoichnology
in Argentina and Uruguay. Likewise, Asian ichnological schools followed a
gradual development. In India, few studies characterized the development of
Modern Approach and the earliest years of the Modern Era. In these early years,
Davitashili (1945) coined the term ichnocoenosis to indicate the traces of a bio-
logical community (biocoenosis); the term was also independently proposed by
Lessertisseur (1956) .