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mian, because he can find no paleontologic or stratigraphic break to separate them from the Carboniferous. He finds 16 genera characteristic of the Carboniferous, and 7 genera not thought to antedate the Permian in Europe, but associated with genera not thought to occur later than the Carboniferous. Meek^[1] says that Fusulina, which occurs in great numbers in the uppermost Carboniferous beds of Nebraska, is considered in Europe to be mainly if not exclusively a Lower Carboniferous genus. In this, however, he was mistaken; his opinion dates from a time when most geologists were inclined to place all Carboniferous limestone in the Lower Carboniferous. But it is now known that the Carboniferous limestone occurs in the Upper Carboniferous about as often as in the Lower, and the Fusulina limestones of Sicily and Russia grade over into beds of undoubted Permian age. This is also true of corresponding beds in the upper part of the Carboniferous of Texas. In fact the Fusulina beds are always either Upper Carboniferous or Permian, in eastern Europe and Asia, and nearly always in America.

Although undoubtedly believing in continuity of life and formations, Meek seems to have based his reasoning on the old idea of catastrophies, since he thought that the absence of a paleontologic or stratigraphic break was a sufficient reason for calling the beds in question Upper Coal Measures rather than Permian. A large majority of the genera and species are characteristic of the Carboniferous, and this Meek thinks sufficient to offset the fact that several genera previously considered typical of Permian^[2] are present.

In the Upper Coal Measures of Arkansas out of 51 species, there are 25 in common with the doubtful strata of Nebraska, and 6 other species are common to the Nebraskan Permo-Carboniferous and the Lower Coal Measures of Arkansas, but have not yet been found in the Upper Coal Measures of the latter