564 AMERICAN ASSOCIATION 
gruous aspect to the area, especially when we recognize the generally ac- 
cepted inse that the source of the sediments has been to the eastward 
of these its. 
- A few years after the close of the survey it was ascertained that in 
Delaware nu lying above the sandstones of Oneonta, there were sev- 
eral hundred feet of gray greenish and other sandstones and shales, con- 
taining the characteristic fossils of the Chemung group 
At the same time it was ascertained that the beds below the Oneonta 
sandstone in Schoharie and Otsego counties contained no characteristic . 
i i han 
cing t 
common characteristie species of that group. Waiting opportunities for 
farther investigation the results of these observations were not published, 
though the error has been partially corrected in the geological map pub- 
lished by the Geological Survey of Canada. 
Later observations have served to verify the earlier conclusions, but 
there has been no opportunity of tracing out in a complete and satisfac- 
tory manner the limit of this sandstone formation 
An examination of the Hamilton group along the valley of the Scho- 
harie creek, has shown that the more argillaceous deposits, with marine 
fossils, are succeeded by coarser beds with remains of land plants, and in 
the neighborhood of Gilboa numerous trunks of large tree-like plants 
have been found standing in the position in which they had grown. The 
entire thickness of the formation is not less than three thousand feet, and 
this is succeeded by the red and gray sandstone and shales originally de- 
scribed as the Oneonta and Montrose sandstones 
The entire thickness of this sandstone in Schoharie and Delaware 
counties has not been ascertained, but in the adjacent county of Otsego 
it is not less than five hundred feet, and is characterized by the diagonal 
lamination especially in the gray beds, and many of the layers contain 
remains of land plants. 
The characteristic fossil Cypricardites * of Vanuxem is found in a shaly 
bed at the bas the sandstones in Richmond's quarry near Mt. Upton, 
immediately ife a plant bed which, so ee; as at present determined, 
belongs to the upper part of the Hamilton p. 
iai: sandstone so far as observed, Pie contains remains of fishes, and 
ong them scales of Holoptychius, but all those seen had proved of 
in species from those of the Tioga red sandstone. 
Lyin he south and above the sandstones we have the series of beds 
before referred to. containing the characteristic fossils of the Chemung 
group, and above this the sandstone and conglomerate of the top of the 
Catskill mountains. 
ia EE E tincidu 
Cairill on. 
si C. angusta are both varieties of form due to pressure. 
The shell. ae is not a true Pa e 
