20 THE CANADIAN NATURALIST. [Vol. ix. 



As regards the belt of Potsdam rocks — upper, middle and 

 lower — which have been described in the Geological Survey Re- 

 port for 1866-69, pp. 119-141, I must state, that after having 

 carefully examined some portions of these supposed Potsdam 

 rocks, I hold that there are no reasons whatever for separating 

 them from the Levis formation, either stratigraphical or palaeon- 

 tological. Obolella, graptolites, and fragments of other fossils, 

 too indistinct to be determined, have been found in them. 



On the south-eastern side, the fossiliferous belt is bounded by 

 a line which, commencing on the United States boundary near 

 St. Armand, runs on a course nearly parallel with the St. Law- 

 rence, passing through the townships of Dunham, Brome, Shefford, 

 Stukeley, Melbourne, Cleveland, Tiugwick, Chester, Halifax 

 and Leeds, to the vicinity of St. Marie on the Chaudiere. Be- 

 tween St. Marie and St. Claire on the Etchemin River, the 

 strata which I have referred to division 2 increase greatly in 

 width, cropping out, apparently unconformably, from beneath 

 the fossiliferous belt and separating it from division 3. The 

 boundary we have been tracing of the Levis formation is here 

 suddenly deflected to a course nearly north for some sixteen or 

 eighteen miles, viz. from St. Claire to St. Vallier, where it again 

 turns north-east, and beyond this it has not yet been defined 

 with certainty. It may be that this apparent unconformity is 

 really a fault which running transverse to the strike brings the 

 Levis black slates and limestone conglomerates into contact with 

 a set of strata which lithologically can not in this part well be 

 distinguished from the typical Sillery sandstones of New Liver 

 pool, Sillery Cove, &c., above Quebec, or from those of Acton, 

 Roxton and Granby, which they still more nearly resemble, and 

 which there are some reasons for supposing may occupy a similar 

 unconformable position beneath the Levis formation. The dis- 

 tribution of these sandstones as indicated on the unpublished 

 map of the Eastern Townships very forcibly suggests this idea. 



Division No. 2 embraces a great variety of crystalline and 

 sub-crystalline rocks ; coarse, thick bedded, felspathic, chloritic^ 

 epidotic and quartzose sandstones, red, grey and greenish siliceous 

 slates and argillites, great masses of dioritic, epidotic and ser- 

 pentinous breccias and agglomerates, diorites, dolerites, and 

 amygdaloids, holding copper ore ; serpentines, fe!sites, and some 

 fine grained granitic and gneissic rocks, also crystalline dolomites 

 and calcites. Much of the division, especially on the south- 



