54 



Comparison of Eastern Canadian Sections with the Section on the 



Credit River 



The differences between the Richmond of the island of Anticosti and of the 

 Credit river are very marked. Very few Anticosti species occur on the Credit 

 river with the exception of certain very wide-spread corals, such as Columnaria 

 alveolata, Calapoecia cribriformis , and Streptelasma rusticum. Another great 

 difference is the almost total absence of trepostomatous bryozoans in Anticosti. 1 



Farther west we find that the sections at Nicolet river and adjoining 

 localities in western Quebec and eastern Ontario resemble somewhat more 

 strongly the Credit River section, but even here the differences are still marked. 

 In the first place, the coral reef is missing from the former sections, and one passes 

 directly upward from strata equivalent to the Waynesville into the red Queenston 

 shales. In the second place, the Anticosti brachiopods, Strophomena hecuba, 

 Strophomena fluctuosa, and Rhynchotrema perlamellosa, which are so abundant 

 in western Quebec, are missing from the Credit river. Foerste does describe 

 a stratigraphic interval in the Nicolet River section which more or less corresponds 

 with the Strophomena varsensis zone of the Credit. This interval consists of 

 the rocks from 76 feet to 156 feet below the base of the Queenston. In the 

 upper part of the interval, Strophomena sulcata (or S. varsensis) is common, 

 and in the lower 100 feet Strophomena planumbona is common. Associated 

 with the latter species at various levels are Catazyga headi, Heterotrypa prolifica, 

 and Hallopora subnodosa, which also are associated with it on the Credit. A 

 study of the Bryozoa from the upper levels of these eastern regions may bring 

 to light a fauna corresponding to that of the Streetsville member. 



Detailed Description of Sections on the Credit River with Complete 



Faunal Lists 



Port Credit, which is at the mouth of the Credit river and near which the 

 lowest exposure on the river is situated, is reached directly by the cars of the 

 Toronto and York radial railway; it is not more than a forty minutes' journey 

 west of the city limits. The exposure which is about a mile west of the terminus 

 of the radial must be reached on foot. It is here that the rocks of the Humber 

 member are seen. 



The village of Streetsville, about six miles up the river from Port Credit, 

 is reached directly by the Canadian Pacific railway. Section No. 14, where the 

 Streetsville member of the Richmond and its included bryozoan fauna can best 

 be seen, is directly opposite the middle of the village. The Stromato cerium 

 reef and the Columnaria reef can also be seen here, but the latter is better exposed 

 immediately above Castler's bridge, a little more than a mile farther up the river. 



The outcrops of the Strophomena varsensis zone at the base of the Erindale 

 member of the Richmond with its bryozoan reef are not so accessible. This 

 zone can best be studied at Section No. 8 on Mullet creek which flows into the 

 Credit river one mile northwest of Erindale, the latter village being about two 

 miles south of the station of the same name on the Canadian Pacific railway. 



A detailed account of the various sections exposed on the Credit river with 

 complete faunal lists follows. 



The base of the whole, series, at the bottom of the quarry near the mouth 

 of the river, is 234 feet above sea-level; the figures given with each section, 

 indicate the position in a vertical column above this datum level, not the actual 

 elevation above sea-level. 



^chuchert and Twenhofel, Bull. Geol. Soc. Amer., Vol. 21, No. 4, p. 700. 



