LOWER SILURIC SHALES OF THE MOHAWK VALLEY 35 



Investigations of these two sections have shown that both lack 

 the base or the contact with the Utica beds. A comparison with 

 the sections of Starch Factory and Ferguson creeks near Utica 

 indicates that the Frankfort and Ilion sections begin closely above 

 the Utica shale. This is also evident from the fact that on the other 

 side of the Frankfort section only two miles to the east, the Utica 

 shale is still exposed on Fulmer creek south of the village of 

 Mohawk. The strike of the shale in the latter outcrop will carry it 

 to very near the base of ,,the Frankfort and Ilion sections. 



We found in the rock section at Frankfort which by aneroid is 

 305 feet thick, 1 four bands of shale containing fossils. The first 

 of these was collected 15 feet above the base of the section at the 

 foot of a cliff 60-70 feet high. 



1 Climacograptus typicalis Hall 

 Lingula fragment 

 Leptobolus insignis Hall 

 Camarotoechia sp. 

 Orthoceras sp. 

 Triarthrus becki Green 

 Trinucleus concentricus {Eaton) 



The next fossiliferous band was found about 85 feet above the 

 base at the second bridge over the creek. Here were obtained : 



2 Climacograptus typicalis Hall (large specimens) 

 Prasopora sp. (minute colony) 

 Leptobolus insignis Hall 



Dalmanella testudinaria (Dalman) mut. 

 Rhynchotrema inaequivalve (Castelnau) 

 Modiolopsis sp. (fragment) 

 Orthoceras sp. (septum) 

 Triarthrus becki Green 

 Trinucleus concentricus (Eaton) 



1 Since these beds dip toward the southwest with an angle that locally is 

 5, but in general not more than 2, it is obvious that this figure is too small. 

 Gushing (1905, p. 36) has determined the surface of the Beekmantown to 

 fall from Middleville to Ilion at a rate of somewhat over 100 feet a mile, 

 stating that the line of greatest dip runs somewhat more to the westward of 

 this direction. This line of greatest dip would then come near the direction 

 of the Frankfort section and since a fall of 100 in a mile corresponds to 

 but i of dip, while the average dip in the Frankfort section appears to be 

 perhaps twice as much, it is safe to assume that at least 200 feet should be 

 added, but probably a thickness of between 200 and 370 feet, the latter figure 

 corresponding to a dip of 2. 



