310 " E, Billings on some of the 



ARTICLE XXIII — On some of the Rocks and Fossils occur- 

 ring near Phillvpshurgh, Canada East. By E. BiLLlNGS, 

 E.G.S., Geological Survey of Canada. 



1. Magnesian Limestone and Underlying Slate. 



In the neighbourhood of Phillipsburgh, on the eastern side of 

 Missisquoi Bay, (which forms the northern extremity of Lake 

 Champlain,) there is an extensive exposure of limestone occupying 

 an area of about nine miles in length by two miles in width, ar- 

 ranged in a series of long irregularly parallel ridges, presenting low 

 broken escarpments on their western faces, and gentle slopes on 

 the eastern. The direction of these ridges is for the greater part 

 nearly north and south, and the dip of the strata in general to- 

 wards the east, at an angle of from 10° to 30° ; but in some 

 places for short distances it is from 30° to 80°. On the western 

 side of this rocky tract, next to the bay, the strata are composed 

 principally of magnesian limestone, often arenaceous, and in places 

 traversed by veins and filled with irregular nodules of white 

 quartz. Interstratified with this there are some beds of a nearly 

 pure limestone, very compact and crystalline in texture, and usu- 

 ally white, or white clouded with various shades of grey. There 

 are also occasionally to be met with, beds of limited extent, or 

 rather lenticular masses of a hard white, or yellowish white sand- 

 stone, intercalated between the strata of limestone. It is difficult 

 to ascertain precisely the thickness of these rocks, but it cannot 

 be much less than 400 feet. They constitute the lower half of 

 the series of limestones exposed in this vicinity, and along the 

 shore of the bay south of Phillipsburgh, they rest upon a forma- 

 tion of hard slates, of a dark grey or blackish colour, with numer- 

 ous seams of white calcareous spar. These slates dip towards the 

 east, at an angle of from 30° to 50°, while the limestones which 

 lie upon them have a dip of from 10° to 30° in nearly the same 

 direction. Near the wharf, just below the old block-house, the 

 slates constitute the lower 20 feet of the cliff, but about half a 

 mile south, the limestone comes down to the water's edge. Fur- 

 ther along the slates appear again at the base of the cliff, with 

 the limestones above them. At the Province line, one mile and 

 three quarters south of the wharf, the limestones once more reach 

 the water, but the slates after a short interval are again exposed 

 in the flat point on the north side of the mouth of the Rock river. 



