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underlies and has furnished detrital material to the 

 Cambrian beds and since nowhere in the general Cambrian 

 basin have volcanic rocks been described as occurring 

 interstratified with Cambrian measures. 



The relations of the trachyte to the other Pre-Cambrian 

 strata exposed over a very wide area to the north, is un- 

 known. On the north side of the volcanic rock lies a band 

 of crystalline limestone and the two rocks are in contact 

 for a distance of at least two miles. The constancy of 

 this feature considered in connexion with the nature of the 

 volcanic rock, may be taken to indicate that the trachyte 

 is of the same age as the limestone strata. No decisive 

 evidence is available to indicate whether the igneous rock 

 is stratigraphically above or below the limestone. 



The band of crystalline limestone extends in a southwest- 

 northeast direction for at least 4 miles (6-4 km.). At the 

 end of the path traversing the band of trachyte, the contact 

 between the volcanic and the crystalline limestone follows 

 southwesterly along Mount Pleasant avenue. On the north 

 side of this road are many exposures of white crystalline 

 limestone traversed by broken and bent dykes or sills of 

 diabase. To the northeast, the full width of the band of 

 limestone is exposed on the eastern shores of Lily lake. 

 In this neighborhood, the width of the crytalline limestone 

 band is about 250 feet (76 m.) . To the southwest, the band 

 rapidly expands to a maximum width of about 950 feet 

 (290 m.). 



The character of the limestone measures is exhibited 

 in a series of exposures along the road known as Lake Drive 

 North which leads from Mount Pleasant avenue past the 

 west end of Lily lake and along the shores of a group of 

 smaller lakes to the north. Where this road crosses the 

 band of crytalline limestone, the rocks at one point are 

 flexed into a syncline and other indications of the deforma- 

 tion of the strata are present. The original bedding planes 

 are indicated by variations in texture, colour, etc. The 

 northern margin of the limestone band is marked by a zone 

 of black rocks, partly slates, partly diabase. 



Just beyond the first cross road on Lake Drive North, 

 are exposures of dense, light coloured quartzite belonging 

 to a band of such rocks having a width of about 800 feet 

 (245 m.). This band of rocks forms the northwestern 

 boundary of the limestone series for some distance both 

 to the northeast and southwest, except where the quartzites 



