PORT HOOD HARBOUR MCINTOSH. 75 



action of the waves was, however, gradually reducing the extent 

 of the land, and its height was being lessened by weathering and 

 running water. In the course of time a line of weakness was 

 found on the seaward side, and a portion was detached from the 

 land mass and formed Henry Island. 



It cannot be stated with certainty how the harbour came into 

 existence, but there is evidence that points strongly to the prob- 

 able way. Its location was an area of structural weakness. 

 (See Fig. 1 . ) The rocks on the present landward side and on 

 the greater part of Smith Island form a part of the Coal Measures. 

 Smith Island has a fringe of the Lower Carboniferous on the 

 northern end, showing also on both sides on the shore underneath 

 the rocks of the Coal Measures. Here is the contact of the two 

 formations, and the upper beds of the lower series consist of soft 

 shales, gypsum, marl, etc. which yield easily to eroding forces. 

 The harbour length is along the strike of these rocks. It is not 

 unlikely, also, that this is a broken or faulted area. The soft 

 rock and the attitude and conditions of the beds were, thus, 

 such 35 to lend themselves readily to rapid wear whether to 

 sub-aerial or wave processes. The slope of the land was in all 

 probability southward, and it may be said with a good deal of 

 certainty that a gentle sloping valley developed about the 

 middle portion of the area largely through stream and general 

 erosion and that it lay oj>en to the south. A slow subsidence of 

 the land bringing it to about the present level allowed the sea 

 to enter this valley depression. The sinking of the land weis 

 general along our coast. All our riverS show it. The sea enters 

 their lower courses. Mabou river, some few miles north of 

 Port Hood, has its lower valley drowned. The tidal waters 

 extend inland to Mabou village some five miles. A depth of 

 fifty feet of water in the Mabou river channel would indicate a 

 sinking of that extent at least, probably much more, as the chan- 

 nel bed has silted up largely since the subsidence. The harbour 

 of Port Hood thus began as a submerged valley of erosion. 

 On the northern side of the depression the rocks were more 

 resistant hard sandstone and withstood the wave attacks and 

 tJie general weathering, so that the harbour lay sheltered from 

 the northern gales by a neck of land perhaps a half-mile wide. 



