CHAPTER III. 



EXPLORATIONS IN THE TRINIDAD CIIA.NNEL. 



IN prosecuting the survey of the Trinidad Channel, we anchored, 

 for short periods each time, at a great many ports on its 

 northern and southern shores ; and in crossing and re-crossing the 

 channel we ran lines of soundings which enabled us to ascertain 

 roughly the general conformation of its bed. Across the seaward 

 entrance of the channel, i.e., from Cape Gamboa on the north to 

 Port Henry on the south, the soundings gave a mean depth of 

 thirty fathoms, showing the existence of a sort of bar, while one 

 mile inside of this the depth increased to two and three hundred 

 fathoms. This was just as we expected ; the bar across the 

 entrance representing the terminal m.oraine of the huge glacier 

 which originally gouged out the channel, and whose denuding 

 action is abundantly recorded in the scorings, planings, and stria- 

 tions so nalpable on all the hard rocks of these inhospitable shores. 

 At Port Henry, on the southern side of the entrance to the 

 channel, we anchored several times. The scenery here is very 

 grand. A clay-slate rock enters largely into the formation of 

 the hills, its highly inclined strata forming jagged peaks and 

 ridges of great height ; while the low-lying rock about the coast 

 is a friable syenite traversed with dikes of greenstone. Imme- 

 diately to the south of our anchorage was a lofty ridge of 

 clay-slate hills, terminating above in a multitude of vertical 

 columns of rock, which from our position on board reminded 

 us of a cluster of organ pipes, and suggested the name which 



