[bailky] gypsum deposits OF NEW BRUNSWICK 5 



of considerable dimensions (Plate II), some of them occupied at their 

 mouths by never melting snow, occur. Some noticeable hills of till 

 are found, but the district is remarkably free from the presence of large 

 erratics. The soil, as a rule, is very fertile, supporting a varied and 

 luxuriant forest growth. 



As bearing upon their probable origin and history the situation and 

 topography of the plaster beds of Hillsborough are not without signi- 

 ficance. These are indicated in the accompanying sketch map, wherein 

 it will be seen that they are found not far from the eastern end of 

 an elevated tract of yerj ancient rocks extending eastward from near 

 the city of St John and parallel to the Bay of Eundy. It is probable 

 that during the Lower Carboniferous period this ridge was wholly sub- 

 merged, as conglomerates and limestones of the formation named con- 

 stitute the siraimit of Shepody Mountain, now about 1,000 feet above 

 sea-level. 



The geological succession in the immediate vicinity of Hillsborough 

 is, in ascending order, as follows : — 



(1) Rrââîsh hrown and cJwcolate, sometimes gray, calcareous 

 conglomerates and sandstones, with clayey and marly beds, the con- 

 glomerates containing pebbles of granite, syenite, slate and other 

 metamorphic rocks, the whole well stratified and indicative of rapid 

 deposition under the influence of strong currents in shallow waters. 

 In places these rocks show the presence of albertite in small veins or 

 scattered particles. They have an exposed thickness of 60 or 70 feet, 

 whicb. however, is but a small part of their total thiclcness as seen 

 elsewhere. 



(2) Gray bituminous limestone, thin bedded or flaggy, also holding 

 small veins of albertite. The limestones are essentially non-fossiliferous, 

 though upon some surfaces are to be seen small cylinders apparently 

 of organic origin, of which the true nature cannot readily be made 

 out. The nature of the beds indicates their deposition or precipitation 

 in quiet waters too shallow or too impure to favour the development 

 of organic life. The thickness of the limestones is about 30 feet. 



(3) Gypsum and anhydrite. These deposits follow immediately 

 •upon the limestones, as observed at many points. They are also fre- 

 quently well stratified with an aggregate thickness of about 200 feet 

 (see Plate III). They are in places quite compact, in others much shat- 

 tered, and are usually extensively divided by vertical joint-planes, made 

 more evident at the surface by the development, through solution, of 

 sharp pinnacles or castellated forms, or, on faces of excavations, by 

 steeply inclined or vertical clefts, widened by water and subsequently 



