LOWER SILURIAN SYSTEM OF EASTERN MONTGOMERY CO. 467 
4 Thin to thick bedded limestone, characterized 
by abundant individuals of Rafinesquina 
miternatia, Trenton. 38’ 402” 
3 Dark colored lumpy limestone, characterized 
by Columnaria alveolata. Black river. O's=.3202" 
2 Dove colored very fine grained limestone, 
characterized by Phytopsis .tubulosa. 
Birdseye. Maes 
1 Thick to thin bedded, flinty, arenaceous lime- 
stone. Calciferous. 350’= 350’ 
Discussion of maps and sections 
On the geologic map of the state of New York published in 
18441 the Califerous is shown as extending northeasterly from 
Rotterdam and westerly along the Mohawk on the south side of 
the river, extending a mile or more to the south. On the map 
which accompanied the New York mineral exhibit at the Colum- 
bian exposition,” the Calciferous and Trenton stages are not separ- 
ately mapped. The eastern and southern boundary of the lower 
Ordovician is indicated as extending from Hoffmans to West 
Charlton and northward, and on the south side of the Mohawk 
for two miles south of Pattersonville and thence westerly along 
the Mohawk joining that at Tribeshill. The Utica-Hudson river 
terrane adjoins the Calciferous-Trenton along this boundary line 
and also covers the region west of Amsterdam and north of Aiken, 
between Amsterdam and Tribeshill. On the large map recently 
published? the Calciferous and Trenton stages are separately 
mapped. The Calciferous extends from Hoffmans (not from Hoff- 
mans as located on the above map for it is there wrongly located, 
being too far east) north to Galway and northward, and westerly 
in a narrow belt along the south side of the Mohawk to opposite 
Aiken (three miles west of Amsterdam). The Trenton forms a’ 
small patch north of Hoffmans and extends along the southern 
1The full title of this map is, ‘‘Agricultural and geological map of the state of New 
York by legislative authority 1844.”’ 
Economic and geologic map of the state of New York showing the location of 
its mineral deposits, by Frederick J. H. Merrill, director New York state museum, 
1894, 
®Geological survey of the state of New York. Preliminary geological map of New 
York exhibiting the structure of the state so far as known, prepared under the direction 
of James Hall by W. J. McGee. Published by authority of the legislature of the state 
of New York. Printed by the U. S. geological survey. J. W. Powell, director, 1894. 
