207 



S — Dinorthis suh(]i<adrata (a). 



7 — Heberteila oceldcntaUa (a). 



6 — Rafinesqnina, Sireptelasma, Platysfiophia, Lcptd'na. 



5 — R ifinesquina, MonlicuUpora. 



4 — DalmaneUa (shaly limestone). 



3 — Bafinesquina. 



2 — Asaphus, calymene. Rafi7iesquina. 



1 — Rafinesquina. 



Ra/jnesqnina remains the dominant fossil for some distance farther down the 

 •creek, where its place is taken by the several varieties of platijs'rophia hiforata. 



No good sections of the Ordovician are to be found in the vicinity of Rising 

 Sun. Numerous exposures of tbe various members may, however, be seen at a 

 number of points. These exposures show that the lower members are, as in the 

 other localities already studied, characterized by the great abundance of Dalma- 

 neUa and Plectamhomfes. These fossils are succeeded in the beds next above by a 

 number of species of TrepoMomata, which in places completely fill the rocks. 



.^bove the Bryozoa beds Ralinesquina alternata becomes abundant, though 

 of course occurring in limited numbers at almost every level. Next fol- 

 lows the zone of PI'ily.<(rophia biforata and its varieties. This is in turn succeeded 

 in the tops of the hills by a zone in which a varietal form of Rafine^quiyia alter- 

 nata is abundant, to the exclusion in places of almost every other fossil. The 

 higher zones are not pre^ent in the vicinity of Rising Sun. 



Vevay, in Switzerland county, is one of the best localities in the State for 

 the collection of Ordovician fossils, and especially of the various forms of Platys- 

 trophia. Two detailed sections were measured at this place. These are det-ig- 

 nated A and B. Section A begins at the head of Main Cross street and extends 

 up the little gully just east of the Orphan Asylum, 



This section (A) is as follows ('i 1, 38 A.) : 



Ft. In. 



87— Covered to the top of the hill 80 



86 — Limestone with Platystrophia and Heberteila 6 



85 — Yellowish argillaceous sandstone 4 



84 — Thin-bedded limestone containing P/a<vs^;•opAia and Heberteila.... 12 



83 — PlatyMrophia biforata 6 



82 — Yellow sandstone 4 



81— Covered 3 3 



80 — Argillaceous arenaceous limestone 4 



79 — Some covered, mostly thin layers with Rafinesquina 14 



78 — Limestone with Rafinesquina and Bryozoa 5 



77— Covered 3 8 



76 — Compact limestone with Rafinesquina 4 



