12 
INTERPRETATION OF FOSSIL PLANTS 
otherwise temperate assemblages anywhere, they indicate contri¬ 
butions by the sea-drift, and if observations can be accumulated 
in sufficient numbers, they will prove exceedingly useful in the 
reconstruction of Cenozoic seaways and the paths of Cenozoic 
ocean currents. 
Land-derived vegetable material is also frequently found by 
oceanographers in deep waters, that is from 1000 to over 2000 
fathoms in depth, as for example in the East Indies,^ as reported 
by Murray and Reynard, the Antilles as noted by A. Agassiz,^ or 
off the west coast of Central America as described by the same au¬ 
thor.^ Such occurrences are always in muds and consist of macer¬ 
ated vegetable refuse associated with such resistant plant remains 
as stems, palm leaves, ligneous fruits, or coriaceous leaves. If the 
latter are resistant enough to resist breaking and disintegration 
more or less successfully, they will still show the effects of micro- 
mial action and incrustation, which proceed more rapidly in marine 
than in fresh waters. Hence the picture of possible confusion that 
such occurrences will present to the paleontologists of a future era 
are very much exaggerated, and similarly if such have occurred in 
the past their decipherment is now perfectly possible. 
Land plants sufficiently well preserved for botanical determin¬ 
ation are frequently found in shallow-water, marine sediments. 
These will rarely be found in limestones, although a considerable 
number of such instances have been recorded. They will com¬ 
monly be found in the clays of coastal lagoons or estuaries. In 
such situations the condition of preservation and the botanical 
representation will tell the story. No general rules can be form¬ 
ulated but each special case becomes a matter of inductive rea¬ 
soning from a sufficient knowledge of present and past ecological 
groupings and environments. For example leaves of large size, 
or those with acuminate tips, or long petioles, will usually be 
broken, and compound leaves will lose more or less of their leaflets 
or lobes if there has been any trituration by waves. Where the 
plant containing clay lenses are of small extent in a prevailingly 
sandy formation as in the Eutaw formation (Late Cretacic) of 
Georgia ^ the recognizable plant species will be few in number 
and will represent only coriaceous, decay-resisting forms. 
1 Deep Sea Deposits, pp. 9S-1(>1, Challenger Rept. 
2 Mus. Comp. Zool. Bull., Vol. XIV, p. 391, 1884. 
zidetn., Vol. XXI, pp. 187-197, 1891; Vol. XXIII, p. 12, 1893. 
4 U. S. Geol. Surv., Prof. Paper 84, p. 121, 1914. 
