546 ON THE GEOLOGY OF ST. JOHN. 



These open moorland tracts are known as " Barrens," and are 

 covered with a profusion of heath-like plants.* 



In the upper part of the Little River group, some improvement 

 in the character of the soil is manifest, more especially where vol- 

 canic sediments prevail. 



But the agricultural capabilities of the land underlaid by these 

 beds, as well as those of the highest Devonian group, depends 

 very much upon the presence or absence of diluvial accumula- 

 tions. The soils of the peninsula are indeed not remarkable for 

 fertility, except where sea or river alluvium has been formed, or 

 carboniferous deposits prevail. Large tracts are entirely barren 

 and unproductive. 



Portland Series. — The intricate structure and extensive me- 

 tamorphism of these older beds renders their examination difficult 

 and perplexing. They are introduced here principally on account 

 of their connection with later deposits. Their general appearance 

 has been so well described by Dr. Dawson, that it is only neces- 

 sary to mention some' peculiarities which did not come beneath 

 his notice. Beside the syenitic gneiss observed by him, there are 

 masses of syenite and granite in which no traces of stratification 

 are discernible ; also beds of mica schist and gneiss conglomerate. 

 The upper part of the series is mostly calcareous, consisting of 

 limestone strata separated by deposits of pyritous slates. Several 

 of these are graphitic and contain small fragments of plants. 



Coldbrook Group. — To these calcareous beds succeeds a group 

 of rocks which does not hold a prominent place at St. John, but 

 is largely developed to the eastward of that place. They are 

 well exposed in the valley of Coldbrook, and further east where 

 the following succession may be seen : 



1. Hard greenish grey slate, stratification very obscure. 



2. Conglomerate with bright red slaty paste. 



3. Grey conglomerate. 



4. Coarse reddish grit and conglomerate with purple sandstone. 



Apparent thickness of the whole, 5000 feet. 



* Gaylussacia resinosa, Vaccmium Pennsylvanicum, V. Vitis-Idcea, 

 Cassandra calyculata, Epigoea repens, Gaultberia procumbens, Kalmia 

 angusafolia, Rho<?ora Canadensis, Corema Conradii, &c, are common 

 on the ridges ; while Sedum latifolium, Kalmia glauca, Andromeda po- 

 lifolia, Myrica Gale, and a variety of other species occur in the hollows, 

 which frequently expand into sphagnous bogs. 



