CORRUGATED AND FAULTED STRUCTURE. 463 



In order to determine this structure more closely, carefully arranged col- 

 lections of graptolites were made at various points along a line of section 

 extending from the south side of the St. Lawrence about half a mile below 

 the lower Levis ferry to Fort no. 2. On this section it was found that simi- 

 lar zones occurred at several places : First, at the river itself, in a cutting on 

 the line of the Intercolonial railway ; second, at the foot and in the face of 

 the cliff overhanging the road from Levis to St. Joseph; and, third, at the 

 city hall on the cliff in Levis. At all these places the dip of the beds is 

 very nearly the same, or southeasterly ; but between locations two and three 

 the extension of the overturned anticlinal already described is seen, and 

 shows that the collections from these places are, without doubt, from strata 

 of the same horizon, repeated on either side of the axis, while the structure of 

 the portion between the cliff and the river is really an overturned synclinal. 



Tracing the courses of the other anticlinals which cross the line of section 

 to the southeast, these were found in all cases to be clearly indicated by the 

 occurrence of red shales which on following to the southwest become grad- 

 ually broader and merged into the great area of red aud green Sillery rocks 

 of the Point Levis and St. Henry section, on which line no fossiliferous 

 Levis anywhere appears. From the line of the Levis section northeastward 

 the Levis rocks gradually acquire a greater extent as we approach the town 

 of St. Joseph, though the anticlinal structure is still clearly visible. It 

 finally appears, therefore, that the Levis formation proper really occupies 

 the synclinal troughs or folds in the Sillery. These have a manifest dip to 

 the southeast, while to the southwest the Levis formation has been entirely 

 removed. In the extreme southeast of the section, the Levis graptolitic 

 shales with their bands of fossiliferous conglomerate appear, at first sight, to 

 underlie directly the great mass of the red and green Sillery shales and sand- 

 stones of the St. Henry section, and such was evidently the view held in 

 1866 ; but on examination of the trenches about the forts, constructed since 

 that date, this apparent superposition of the latter was clearly found to be 

 due to an overturned synclinal in the Levis beds, the outlines of which could 

 be clearly traced. 



Along the coast, both on the south side of the islaud of Orleans aud on 

 the south side of the St. Lawrence, a similar structure doubtless exists; but 

 is complicated by a series of faults. On the island the Levis formation is 

 confined to a small area at the western extremity and brought into contact 

 with the Sillery shales by a line of fault, while the Sillery itself, often pre- 

 senting a wonderful series of folded aud crumpled strata, occupies the entire 

 south side of the island and the greater part of the south shore of the St. 

 Lawrence for several hundreds of miles eastward from Levis, or nearly to 

 the extremity of the Gaspe peninsula. Outcrops of strata holding Levis 



