igoo] Ami- On Some Trenton (Ordovician) Fossii-s. 



239 



imperfeclly — were examined and recognised as forming a regular 

 succession of well-nigh horizontal strata which appear along the 

 Ottawa River front and form a more or less conspicuous series ot 

 cliffs and planes in ascending order until the summit of the high- 

 land is reachtd south of Cumberland, where the Trenton formation 

 and the overlying Pleistocene deposits make their appearance. 

 This locality is evidently a most interesting one inasmuch as it 

 gives the geologist and collector an uninterrupted succession of 

 fossiliferous sedimentary strata from the Calciferous to the Tren- 

 ton at least, without the presence of the faults and folds or dislo- 

 cations so prevalent in the immediate vicinity of Ottawa, which 

 tend to obscure and puzzle the student of geology. 



The following list of species of organic remains collected by 

 Dr. F. S. Jackson in the light-gray, semi-crystalline limestone of 

 Cumberland in i8go, as determined by the writer, are presented in 

 the hope that they may serve to stimulate some of the local collec- 

 tors to visit that interesting locality where our Ordovician forma- 

 tions are so well seen and developed. 



ZOOPHYTA. 



1. Streptelasma corniculum, Hall or allied form. 



ECHINODERMATA. 



2. Criiioidal fragments, not determinable. 



BayozoA. 



3. Branching' form, requires a micro-section before it can be identified 

 with certainty. 



Brachiopoda. 



4. Plectambonites sericea, Sowerby, typical form. 



5. Strophomena fluctuosa, Billings. 



6. Rafinesquina alternata, Conrad (Emmons). 



7. Stropliomena, cf. S. tenuistriata, Sowerby. 



8. Platystrophia biforata, var. lynx, Eichwald. 



9. Rhyncheoma inaequivalvis, Castelnau. 



10. Zygospira recurvirostra, Hall. 



Gastropoda. . 



11. Liospira Progne, Billings. 



12. Trochonema umbilicatum, Hall. 



13. Hormotoma gracilis, Hall. 



14. (?) Omospira Alexandra, Billings, 



