Sea- Cliff of the Lower Saint Laiorence. •'!()!» 



as far south as New England.* While the Lower Saint Law- 

 rence lies in a zone of seismic disturbances, as Laflaniine has 

 clearly shown, f it seems very doubtful whether any great seis- 

 mic movement, or series of movements, along the Saint Law- 

 rence fault line, would elevate 225 miles of coast so evenly. In 

 the case of the earthquake of 1899, in Yakutat Bay, Alaska, 

 recently described by Professors Tarr and Martin,;}: the changes 

 of level along the coast were very irregular, varying from 45 

 feet uplift to several feet depression in distances of a very few 

 miles. Granting that the fracture system along the Lower 

 Saint Lawrence may be much simpler in character than that in 

 Yakutat Bay, and that the seismic movements of the former 

 region ma}' consequently be more regular, it still seems exceed- 

 ingly unlikel/that the Micmac shoreline has reached its present 

 uniform position by sudden earthquake movements. The onty 

 safe conclusion appears to be that it participated in a second 

 great epeirogenic uplift. The difficulty therefore remains, of 

 explaining a long interval of stability between two unstable 

 periods. 



Hypothesis of an Interval of Coastal Subsidence Between 

 Two Uplifts. 



With the principles of shoreline morphology again in mind, 

 Ave may frame a second working hypothesis, and test its validity 

 in the same manner as the first. According to this hypothesis, 

 the sequence of events is, briefly, (a) a differential epeirogenic 

 uplift, causing the emergence of the coast between Matane 

 and Quebec of from 170 to 630 feet, respectively ; (b) a rever- 

 sal of the movement, involving a slow subsidence of the coast, 

 of relatively small measure but perhaps of equal duration ; (c) 

 a second epeirogenic uplift, of unknown rate and duration, 

 likewise of slight vertical measure, — 20 feet. Leading toward 

 the support of this hypothesis there are several lines of 

 evidence. 



Independent evidence of subsidence. — There are clear indi- 

 cations of a post-glacial subsidence of the coast of New 

 England and the maritime provinces, which it may he possible 

 to correlate with the Micmac shoreline. ' Submerged peat bogs 



* See the condensed account of this earthquake in Prof. W. H. Hobbs' 

 "Earthquakes," New York, 1907, pp. 315-320. The chief source of infor- 

 mation is the "Jesuit Relations," translated by Dr. Reuben Gold Thwaites. 



f J. G. K. Laflamme : Les Trembleraents deTerre de Quebec. Proc. Roy. 

 Soc. Canada (3), vol. i, pp. 157-183, 1907. 



% R. S. Tarr and L. Martin : Recent Changes of Level in the Yakutat Bay 

 Region, Alaska. Bull. Geo]. Soc. America, vol. xvii, pp. 29-64, 1906, espe- 

 cially plate 23. 



