No. 89.] 95 



NOTES AKD OBSERVATIONS 



Upon the fossils of the Goniatite limestone in the Marcellus shale of the Hamilton 

 group, in the eastern and central parts of the State of JVew-York, and those of the 

 Goniatite beds of Rock ford, Indiana; with some analogous foi-ms from the Hamil- 

 ton group proper. 



At the base of, or forming the lower member of the Hamilton group, there is a 

 mass of black shale or slate known as the Marcellus shale. In the midst of this 

 black slate there is a band of limestone which is more or less continuous, and 

 which, over a considerable area, divides the Marcellus shales into two parts, a 

 lower and upper member. The lower one is more strictly a slate; while the upper 

 one, from a black slaty mass, passes to an olive or bluish shale, gradually losing 

 its slaty cleavage. As this limestone dies out in a westerly direction, this line of 

 division is not marked, and the Marcellus shale is recognized only as a single 

 member of the group. 



This limestone is charged with Goniatites, and other chambered shells, with 

 comparatively few fossils of any other character. Among the fossils of this rock, 

 I have recognized two species of Goniatites, one of which occurs in great numbers; 

 one of Nautilus or Discites, one of Ctrtoceras, two of Gyroceras, three of 

 GoMPHOCERAs or ApiocERAs, One of Oncoceras, one of Orthoceras, one of 

 Pleurotomaria, one or two of Euomphalus, one Dentalium, one acehpalous 

 shell allied to Edmondia.'', one Leiorhtnchus (the L. limitaris, page 85 of this 

 paper), and a species of Proetus. 



There are probably other fossils not yet ascertained in this limestone, which, 

 however, has rarely a thickness of more than three or four feet, and often less 

 than two feet. In the western part of the State we know two or three other species 

 of Goniatites, Orthoceratites, etc. in the shales of the Hamilton group in a 

 higher position than those of the limestone. 



In the Report of the Third Geological District of New-York, Mr. Vanuxem 

 gave figures and descriptions of two of these Goniatites, the originals of which 

 were placed in the State Collection. Since that period, I am not aware that any 

 published notice has been made of these fossils. 



At Rockford, Indiana, in what appears to be nearly the same geological hori- 

 zon, we find a stratum charged with Goniatites, Orthoceratites, etc. Of the 

 former there are at least three species, one of which is regarded by palceontologists 

 as identical with the European G. rotatorius, a Carboniferous species, while the 

 others are apparently of undescribed forms. In the same association we find Gyro- 

 ceras, Bellerophon, Pleurotomaria, Euomphalus, etc., with a few brachiopo- 

 dous and lamellibranchiate shells. A comparison of these fossils with those of 

 New-York becomes a matter of interest; and to facilitate this object, I have pre- 

 sented the following descriptions and illustrations. In the New- York localities we 

 have one species of Goniatites and one Orthoceratite, occurnng in large num- 

 bers. In the Rockford locality, we have two species of Goniatites and one of Or- 

 thoceratites, likewise occurring in great numbers; while in both localities the 

 other fossils are comparatively rare, or far less abundant. 



The parallelism of these localities is inferred from the fact that the stratum con- 

 taining the Goniatites is clearly above the limestone of the age of the Upper Hel- 

 d<?rberg group, and below the sandstones which are recognized as of the age of the 

 Chemung group of New-York." The exposures at the immediate locality are ob- 



