A paleoecological analysis of the petrified trees in the Specimen Creek area of Yellowstone National Park, Montana, U.S.A
Abstract Petrified trees from specific stratigraphic units of the Specimen Creek locality in Yellowstone National Park have previously been identified at the genera level. The identified woods were plotted on modern climatic ranges. Specific units exhibit the following climatic ranges: • Unit 1. Subtropical to boreal, mostly warm-temperate to cool-temperate. • Unit 5. Tropical to boreal, mostly subtropical to cool-temperate. • Unit 9. Warm temperate to boreal, mostly cool-temperate and boreal. Several features have emerged which suggest that this sequence of layers containing petrified trees does not represent natural communities buried in situ. These are: (1) the presence of uncommon mixture of tree types within a level; (2) the absence of correlation in numerous cases between the vertical fossil trees and the associated microfossils; and (3) the change in composition of tree types from one level to the next. The model proposed by Fritz (1980) permitting some transport of wood and plant remains from different habitats appears at present to offer the best explanation for the observed data.