416 G. L. COLLIE ORDOVICIAN SECTION XEAR BELLEFOXTE 



expansd (Hall) and Protoivarthia hilobaius (Sowerby). Other types occur- 

 ring here are Protowarthla cancellata (Hall), Trochonema amhigua Hall, 

 Liospira progne (Billings), Eotomaria dryope (Billings), Vanuxemia hayni- 

 ana Safford, V. abrupia Ulrich, Cyrtodonia grandis, Ulrich, and Rnfines- 

 quina cmnerata (Conrad). 



In horizon A-16 the limestones are very shal}^ increasinglj^ so toward 

 the Utica horizon. The fossils are confined mainly to the beds of purer 

 limestone, which occur at intervals in the shaly limestone. Trinudeus 

 concentricus and Prasopora Simidatrix orientalis, however, occur in vast 

 numbers in the shaly portion of the rock. The most characteristic fos- 

 sils found are a number of Lingulas, as follows : L. obtusa Hall, L. elongata 

 Hall, L. curta Conrad ; also Trematis terminalis Emmons. In addition, the 

 following fossils occur : Tetradella subquadrata Ulrich, Isotelus platycephalus^ 

 Calymmene callicephala, Hormotoma gracilis (Hall), Conularia trentonensis 

 Hall, Lophospira perangulata (Hall), Whitella subtruncata (Hall), Dahnan- 

 ella testudinaria, Platystrophia biforata, Strophomenafilitexta. 



Horizons A-8 to A-16, inclusive, carry Trenton faunas and may be 

 referred to that formation, though the total thickness, 603 feet, is much 

 greater than the Trenton ordinarily reaches. At the base of the Trenton 

 proper the most typical and common fossil is Orthis iricenaria ; in the 

 middle horizons Plectambonites sericeiis becomes the most characteristic 

 t3^pe; in the upper Trenton Plectambonites disappears for the most part 

 and Dalmanella testudinaria becomes the most marked form. Dalma- 

 nella occurs in very great numbers in the uppermost horizon of the 

 Trenton. The order of occurrence noted above accords well with obser- 

 vations made by Weller in the Trenton of New Jersey.* 



It will be seen from the above enumeration of fossils that the faunas 

 are ver}'- closely related to those of the same age both in New York and 

 in the northwest. Almost the onl}" exception to this statement is the 

 occurrence of Brongniartia in horizon A-8. 



Utica and Lorraine Shales 



Horizon B-1 contains a few fragments of Dalmanella testudinaria and 

 Isotelus platycephalus, hut the most characteristic fossil is Triarthrus becki 

 Green. This form is seen in great numbers at the base of the Utica, but 

 more sparingly above. Its total range appears to be about 300 feet in 

 vertical height. 



Horizon B-2 includes the series of shales belonging to the Lorraine 

 formation. The rocks are not well .ex})osed in the neighborhood of 

 Bellefonte, and the descriptions here given are taken from a study of 

 the exposure at Matternville, a few miles north of Bellefonte. 



*Cieol. Survey of New Jersey Paleontology, vol. iii, p. 37. 



