350 TRANSACTIONS OF THE CANADIAN INSTITLTE. [V"OL. V. 



marls with modern fossils seen on the north-western coast may belong 

 to this series. 



MODERN HISTORY. 



Epoch of Elevation. — At the close of the Liguanea epoch, the land 

 rose to an altitude of not merely the height of the Liguanea series, but 

 to an elevation of 120 feet more. At this time an epoch of considerable 

 erosion was commenced, which is characterized b}' all of the rivers leav- 

 ing the highlands through freshly excavated canyons, where the streams 

 are still deepening their channels. The canyon epoch was more recent 

 than the Liguanea formation, as this last is dissected by them. The 

 evidence of greater elevation than at present is preserved in the 

 valleys and channels crossing the submerged shelf upon the southern 

 side of the island. On the northern side, the evidence is scarcely avail- 

 able on account of the narrow submarine fringe ; but in the little 

 valley of Dry Harbour, which is submerged to a depth of over 200 

 feet with a bar in front of it less than 18 feet below the surface, which 

 could easily be formed by coastal currents as the district has since been 

 sinking, there may be evidence of somewhat greater recent depression 

 than is recorded on the southern side of Jamaica. The occurrence of 

 the large swamp formations at the mouths of many of the rivers, as 

 well as the drowned channels, also indicates the depression subsequent 

 to the modern post-Liguanea elevations of 120 (or 200) feet. 



Hope River leaves the mountain regions opposite the northern end 

 of Long Mountain (see Map, Figure 4, page 337), and its former 

 course was over the Liguanea district, not apparently in modern days, 

 but before the Liguanea epoch, during which time the channel became 

 obstructed to an elevation of about 600 feet above the sea. Upon the 

 post-Liguanea emergence, the Hope River turned across the neck of 

 Long Mountain (see Figure i, Plate V., page 349), and has since made 

 a canyon three miles long. This neck was about 550 feet above the pres- 

 ent sea level. The floor of the upper part of the gorge is now 1 50 feet 

 deep, or about 400 feet above the sea. In the three miles it descends 

 300 feet and abruptly enters a broad valley. The width of the gorge 

 at its base is from 50 to 75 feet, although it is often reduced to 20 feet 

 (Figures i and 2, Plate VL). This canyon represents the amount of 

 post-Liguanea erosion, and throughout its length, it is excavated out of 

 the "White Liinestone." The post-Liguanea elevation was thus suffi- 

 ciently long ago to permit of the formation of catiyons three miles long, 

 and from 1 50 to 500 feet deep. 



All the other rivers crossing- the " White Limestones " have similar 



