GEOLOGIC MAP OF THE TULLY QUADRANGLE 



45 



Cardiff shale 



This name has been applied to the upper beds commonly embraced 

 under the unrestricted term Marcellus shales. These are for the 

 most part blue gray shales at the base, being soft and argillaceous 

 with frequent layers of darker shale. Ascending, the mass becomes 

 lighter in color and near the top are some layers which, on exposure, 

 become very light gray and the darker layers are thin and less fre- 

 quent. Toward the top are occasional thin calcareous layers and 

 small concretions. This division maintains its general character to 

 the east and also westward but in the latter direction becomes 

 thinner. The thickness of this mass is about 175 feet. 



Exposures are found in two ravines on the east side of Onondaga 

 valley, i T /$ and i J / 2 miles north of Cardiff, at the salt well 1 mile 

 south of Cardiff, at the mouth of the Bear mountain ravine 2V 2 miles 

 southwest and also along the dugway road leading to Maple Grove 

 3 miles northwest; likewise in the ravine 1 mile south of South 

 Onondaga; 1 mile southeast from Indian Village; iy 2 and 2 miles 

 southeast from Jamesville. The contact with the succeeding 

 division is best shown near the mouth of Bear mountain ravine. 



The fossils of this rock are of infrequent occurrence and poor in 

 preservation. Toward the top are found impressions ofParodic- 

 e r a s discoideum, Bactrites and Orthoceras and some thin 

 layers contain Strophalosia truncata with Liorhyn- 

 chus limitaris and L. m ulticostata in large numbers. 

 L. limitaris is by far the most abundant species here as it is of 

 the darker shales below and the horizon at which it ceases to be 

 common and where new forms not seen below appear, is taken as 

 the upper limit of the formation. 



Skaneateles shale 



The term Hamilton group as it has been employed in the New 

 York nomenclature has been subject to misuse. The term was 

 originally used by Yanuxem in the form " Hamilton group " to de- 

 scribe certain beds of sandy and argillaceous shales typically exposed 

 at West Hamilton, Madison co. Strictly speaking, the only proper 

 application of the term is to these beds and their stratigraphic equiva- 



