OF CENTRAL CANADA PART V. 31 1 



centricus (fig. 172). Characteristic exposures of these strata occur 

 at Barrack Hill (Ottawa City) ; Green's Creek in East Gloucester ; 

 ne-r Dunning's Mills in Cumberland; near McCaul's Mills in 

 Clarence ; at the High Falls of the South Nation River in Cam- 

 bridge ; and at various sites in L'Orignal, West Hawkesbury, 

 Lochiel. Kenyon, Cornwall and adjacent townships. 



The Utica formation, consisting essentially of dark-brown or black 

 bituminous shales, overlies the Trenton, but occurs only in small 

 areas around Ottawa City, and in parts of Cumberland, Clarence, 

 and Plantagenet. Its more characteristic fossils, as occuring in the 

 shales of the E/ideau and elsewhere in the immediate vicinity of 

 Ottawa,* include several graptolites, as Diployraptus pristis (fig. 132) 

 and other species ; various crinoids, brachiopods, lamellibranchiates 

 and gasteropods; and the trilobites, Asaphus Canadensis (fig. 169) 

 and Triarthrus Beckii (fig. 177). The Hudson River Formation, 

 which follows the Utica Formation in ascending order, is also but 

 slightly developed in this district. It is represented essentially by 

 thin-bedded calcareous sandstones, seen here and there in the town- 

 ships of Osgoode and Russell, and at points near Ottawa City. The 

 more characteristic fossils of the Formation ( Leptcena sericea, fig. 

 196 ; Strophomena alternata, fig. 194 ; Ambonychia radiata, fig. 208; 

 Calymene Blumenbachii, fig. 178; etc., etc.), are referred to more 

 fully under this formation as occurring in the LAKE ONTARIO DISTRICT. 



These various strata, as stated above, are overlaid very generally 

 by Drift deposits and other superficial accumulations. The Drift for- 

 mation is represented by boulder clays in some places, and by gravel 

 heaps and scattered boulders in others. These latter are arranged 

 here and there in long ridges which occasionally cause obstructions 

 and rapids in the river courses, as at Green's Creek and L'Orignal on 

 the Ottawa. At Barrack Hill and other places around Ottawa, and 

 also in other parts of the district, the limestones beneath the boulder 

 clay often shew ice-grooves and other signs of glacial action. The 

 grooves and striae have mostly a south-east direction, but some are 

 only a few degrees east of south. To these Drift or Glacial deposits 

 proper, succeed in many places beds of stratified clay, sand and gravel, 

 as a rule free, or practically free, from boulders. They contain shells 



* See a complete list in papers by Mr. Ami, contributed to the Field Naturalists' Association 

 of Ottawa. 



