williamb. J THE FINAL NEW YORK REPORTS. 51 



of American geology. The final reports of the State of New York 

 were published in the years 1842-M3. 1 



The classification which appears in the several final reports was 

 already outlined by Conrad in 1841, and, in fact, the general order of 

 strata was given in his report for 1839. The development of the classi- 

 fication of the rocks for New York State will bear minute study, and 

 will yield valuable suggestions to students of systematic geology 

 The rocks with which the New York geologists were concerned were 

 mainly confined to the series from the Archean or Primary rocks 

 through the Paleozoic as far as to the base of the Carboniferous. The 

 geologists, although working together, had the State separated into 

 four divisions and developed the stratigraphical geology of each dis- 

 trict independently, observing the character of the individual rock for- 

 mations, their order, and the fossils contained in each. Conrad was 

 the paleontologist during the field operations, and his contribution to 

 the work was the identification of the fossils sufficiently well to make 

 recognizable the relationship between the fossils of the New York 

 rocks and the formations of England which had been studied so care- 

 fully and were so elaborately defined by Murchison and Sedgwick. 



The fossils of the British sections had been described by John Phil- 

 lips, J. De C. Sowerby, and Lonsdale, and their descriptions were 

 accessible to the American geologists as early as 1839. Conrad had 

 used this Silurian system with its fossils as a basis for the classification 

 and correlation of the rocks of New York State. The attempt was 

 made in 1839 to divide the New York rocks in accordance with Murchi- 

 son and Sedgwick's classifications, and the fossils found in them, corre- 

 sponding with those of the British rocks, were enumerated. Thus, in 

 the third annual report, Conrad gave a " table of formations," showing 

 the order of superposition and some characteristic fossils of the Transi- 

 tion strata. The Carboniferous strata (No. 10) were mentioned (but 

 are in Pennsylvania), then the rocks of New York 2 were distributed as 

 follows : 



Under the " Old Red sandstone group (Murchison)" he placed: 



u 9. Old Eed sandstone (?) and Olive sandstone," which, we find 

 from study of the reports, includes the Chemung aud Catskill groups. 



"8. Dark-colored shales and black slate," which appears to be the 

 Hamilton and Marcellus. 



Under " Medial Silurian system," are found " (7) Gray Brachiopodus 

 sandstone, Helderberg sandstones, Helderberg limestones, second Peu- 

 tamerus limestones; (6) Gypseous shales, Rochester shales, and Pent- 

 amerus limestones, (5) Green slate, Lenticular iron, etc., and (4) Niagara 

 sandstone (red)." 



1 The editors of these final reports were William W. Mather, report of the first district, published 

 1843 ; Ebenezer Emmons, report of the second district, 1842 ; Lardner Vanuxem, report of the third 

 district, 1842, James Hall, report of the fourth district, 1843. It is important also to rememherthat T. 

 A. Conrad published his final report on the paleontology of the survey in the year 1841, in the fifth 

 annual report. 



2 N. Y. Geol. Survey, 3d Ann. Rep., pp. 62-63. 



