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1902] Annual Report — Geological Section. 257 



List of the fossils of the Utica formation found in the excavations made for the 

 Main Drain of Ottaiva, April 2jth, igoi, on the occasion of the first 

 excursion of the Ottawa Field-Naturalists' Club. 



1. Leptograptus flaccidus, Hall. 



2. Orthograplus quadrimocronatus, Hall. 



3. Climacograptus bicornis, Hall. 



4. Leptobolus insignis, Hall. 



5. Lingula Progne, Billings. 



• 6. ,, Cobourgensis, Billings. 



7. ,, cuta, Hall. 



8. ,, obtusa, Conrad. 



9. Orthis testudinaris, Dalman. 

 ^ 10. Zygospira modesta, Say. 



f II. Trorholites ammonius, Emmons. (Large, fine specimen.) 



12. Orthoceras teniiistriatum, Hall. 



13. Orthoceras lamellosum, Hall. 



14. Modiolopsis, sp. indt. 



15. Asaphus latimarginatus, Hall. ( = A. Canadensis, Chapman.) 

 V 16. Triarthurus spinosus, Billings. 



17. ,, Becki, Green, (both in the nepionic and adult stages). 



Amongst the most interesting^ finds made on that occasion 

 was one of the embryonic forms of Triarthrus Becki, a 

 characteristic trilobite of the Utica formation. Primordial 

 features present in the specimen indicate clearly the remote origin 

 of this generic form whose nearest relatives so far known belong 

 to the Cambrian period, and whilst its pygidium or tail appendage 

 is quite diminutive, its head or cephalic shield is comparatively 

 large. Such larval forms of this trilobite are rather scarce, but 

 deserve special attention. The writer has found a number of them 

 during his researches in the Utica of the Ottawa district, and 

 hopes to be able to put the material together some day. It may 

 be added here that considerable progress was made during the 

 past year in the study of the fauna of the Utica, and as soon as 

 drawings can be prepared which will serve to illustrate the fine 

 Utica fossils of this region a much needed contribution to the 

 palaeontology of a portion of the Ordovician succession about 

 Ottawa will soon follow. 



Britannia. The second excursion of the season was held at 

 Britannia. The geological section visited the extensive excava- 

 tions made by the Metropolitan Light, Heat and Power Company, 



