Report of the State Geologist. 261 



only a short distance southeast of Unadilla Forks and approximately 

 3.2 miles southwest of A497B. A circuitous roadway leads from the 

 village to the top of the " mountain " and some distance up the hill, by 

 the roadside, is the lowest exposure 498A'. The rocks are thin, arena- 

 ceous shales, breaking up very irregularly, and iron-stained when 

 weathered. The lithologic apj^earance of these shales is similar to those 

 of A497A2. The fauna is as follows: 



Llorhynchus multicosta, Hall. 



Numerous specimens of the typical Hamilton form, also smaller 

 forms apparently similar to the specimen figured by Prof. Hail as " a 

 young individual" of this species. (See Pal. N. Y. vol. iv., pi. 56, 

 fig. 26.) 



AmbocceUa innbonata, Hall. 



One specimen shows both concentric and radiating striae, while four 

 internal impressions of the dorsal valve have a median depression 

 'extending from the umbo to the front of the valve. 



Chonetes sp. Small specimens (with one exception) imperfectly pre- 

 served ; probably C setigera, Hall or C lepida, Hall. 



Paracyclas Urata, Conrad. 



Nuculites oblongatus, Conrad. 



Nuculites trlqueter, Conrad. 



Orhiciiloidea sp. 



Several fragments which have not been identified with certainty. 



A ledge on the western side of the " mountain " forms a bluff near 

 the summit and this has been called 498A2. There are from 50' — 75' 

 of arenaceous shales and sandstones. The strata at the base of the 

 ledge are of considerable thickness and one compact sandstone stratum 

 8" in thickness would apparently make a fair quarry stone. Weathering, 

 however, indicates the presence of iron. The layers higher in the bluff 

 are thin at d irregular and in view of the large amount of "stripping" 

 that the quarrymen w ould be obliged to do, it is not probable that a 

 profitable quarry could be opened. The sandstones and arenaceous 

 shales do not contain an abundant fauna, either in reference to num- 

 bers or species, as may be inferred from the following list : 



JRhynchonella congregata^ Conrad (?). 



The specimens are mostly internal impressions, common in occasional 

 layers of arenaceous shale. Unadilla Forks is one of the localities 

 given by Prof. Hall for the above species. 



Spirifer mediaUs, Hall (?). 



Only imperfect specimens. 



Spirifer granidifer, Hall. 



