180 Forty-sixth Report on the State Museum. 



My first examination of the Oneonta region in 1844 disclosed 

 the fact that the Oneonta sandstone, described as lying upon 

 the Chemung group, really rested directly upon the shales 

 of the Hamilton group, and the quarries cited by Yanuxem as 

 containing Chemung fossils really contained only characteristic 

 fossils of the Hamilton group. This erroneous idea of the order 

 of succession had entered into the discussions of the relations of 

 the Hamilton and Chemung groups, and the arenaceous beds of 

 the former group in that region of country had been referred to 

 the age of Chemung group. Farther examination on the hill 

 summit, in the neighborhood of Oneonta, showed very clearly 

 that rocks carrying characteristic Chemung fossils rested directly 

 upon the top of the Oneonta sandstone. In exploring the 

 country further southward and south-eastward, there was found 

 a belt of gray and greenish-gray shale and sandstone carrying 

 Chemung fossils, lying above the Oneonta sandstone, and suc- 

 ceeded above by red marls and gray grits and sandstones w^hich 

 formed a part of the Catskill group in its western extension. 

 Repeated examinations of this region through several years, 

 although cursory in their nature, confirmed these first observa- 

 tions ; but it was not until 1870-7 i that the country was mapped 

 with anything like accuracy in regard to the relations of these 

 formations. This map, however, was never published, and it 

 remains as a record of the results of field work of 1870, although 

 the work of previous years had been incorporated. Following 

 this period for several years no extended or systematic field 

 work was carried on, and our increasing information was 

 obtained from desultory observations, and the comparison of 

 fossils collected in the region named ; but the subject of inquiry 

 was never lost sight of, and scarcely a year passed without adding 

 something to our knowledge or suggesting some new point of 

 inquiry. 



In 1880-81 still further progress was made in the investigation 

 of the Oneonta region and the extension of these formations to 

 the east and west. This w^ork, chiefly done by Mr. Andrew 

 Sherwood, under my immediate direction and supervision, con- 

 firmed and extended the conclusions reached in 1870, and in 

 previous years. The result of these investigations was recorded 

 upon a post route map of the State, with the following title and 

 legend. 



