OLDEST PETRIFIED FOREST GOLDRING 319 



the present area of the Atlantic. This shallow sea covered the 

 interior of the State and country and received the heavy drainage 

 from this eastern land mass. The southwesterly flowing rivers 

 brought down debris of the primitive vegetation with which that 

 lost land was wooded, and scattered the remains, leaves, stems, 

 branches, etc., through the vast delta and shore deposits. Perhaps 

 nowhere else in the known records of the rocks is there such an 

 extraordinary accumulation of the land flora of this geological age 

 as in these sands which underlie the slopes of the Catskills westward 

 into the Allegheny Plateau. Plant remains were mingled with the 

 earliest of the fresh-water mussels which burrowed in the sands of 

 the river mouths; at times the rivers carried the forest growth far 

 out among the marine deposits and it was mingled with the animal 

 remains of the salt sea. This close intermixture of terrestrial and 

 marine conditions is most abundantly shown in the lower or earlier 

 part of the Catskill terrane. The coasts of those days were very 

 unstable, which would give a swampy shore line. Forests of prim- 

 itive trees grew along these shore lines, spreading down to the water's 

 edge. Gradual submergence of the coast carried these trees beneath 

 the water and the sediments piled up over their bases. At a later 

 period when the sinking basin was again filled by deposits the forest 

 again crept down to the water's edge. The discovery of these hori- 

 zons of fossil tree stumps shows that three successive forests flour- 

 ished here, were submerged, destroyed and buried. The fact that 

 the stumps are buried in a fairly coarse sandstone indicates a rapid 

 destruction and burial. 



The geologic horizon of the occurrence of the Gilboa trees appar- 

 ently is the Ithaca formation. The Oneonta is characterized by red 

 beds and they are not found as low as any horizon containing tree 

 stumps. Red beds characteristic of the Oneonta are seen a few feet 

 above the highest tree horizon at the Manorkill. Collections made at 

 a higher horizon four miles to the south at the intake of the tunnel 

 show a prevailing Ithaca fauna ; and it is therefore apparent that we 

 have an intermingling of Ithaca and Oneonta sediments. The 

 fresh-water unio, Amnigenia catsMllensis^ occurs in a massive sand- 

 stone one and a half miles northeast of Gilboa, some 600 feet above 

 the level of the Schoharie Creek at Gilboa, which clearly indicates 

 that the horizon of this shell is above that of the tree trunks found at 

 Gilboa. The Ithaca fauna is also present on the hillsides above 

 Gilboa ; and all this indicates that we have in this area an interfinger- 

 ing of the Oneonta and Ithaca sediments. 



