348 MINERALS AND GEOLOGY 



Wolfestown, Stanstead, Leeds etc. Roofing Slate (in part belonging 

 to altered Silurian beds) Melbourne, Orford, Cleveland, Richmond. 

 Whetstones Stanstead, Bolton, Kinsey. 



Fossiliferous Palceozoic Formations ; As recognised within the 

 Appalachian district, these comprise, in ascending order, represen- 

 tatives of the Calciferous Formation, with Lower Silurian, Upper 

 Silurian, Devonian' and Lower Carboniferous strata. 



The Calciferous Formation or geological horizon corresponding 

 practically to the higher part of this is represented by the uncrystal- 

 line portions of Sir William Logan's " Quebec Group." This series 

 of strata is made up essentially of grey and greenish (in places glau- 

 conitic) sandstones, many of which hold small pebbles of white quartz, 

 interstratified with olive-green, red, purplish, and gray shales, form- 

 ing the so-called " Sillery formation " ; and of grey, red, and black 

 graptolitic shales associated with limestone conglomerates and yellow- 

 ish-grey dolomitic beds, making up the " Levis formation." The sub- 

 divisions of Sillery and Levis, however, should properly be abandoned, 

 the two sets of strata forming practically but a single series of varied 

 mineral composition. The sandstones along parts of the Gaspe coast 

 as between the St. Anne des Monts and Grand Michaud rivers, 

 more especially have been worn by denudation into more or less 

 isolated pillars which form prominent objects as seen from the Gulf. 

 Hence the name of " pillar sandstones," by which they were at one 

 time known. The black and other coloured shales are especially 

 characterised by the presence of ^ compound graptolites," represented 

 by Loganograptus, Phyllograptus and related types (ante, page 228); 

 and the calcareous beds contain many peculiar trilobites species of 

 Agnostus (fig. 167 bis.) Dikrlocephalus (fig. 171), Batliyurus, Arionel- 

 lus, etc. The shales and limestones contain also, in many places, 

 examples of characteristic brachiopods, as Obolella pretiosa, Lingula 

 Quebecencis (fig. 204), and small species of Orthis, Leptczna, and Cam- 

 erella. 



As regards general distribution, these Calciferous (Quebec) strata 

 form a practically continuous band along the western and northern 

 edge of the central crystalline areas of the district, from the province 

 line at the head of Lake Champlam to the extremity of Gaspe ; and 

 they are well displayed at Sillery on the St. Lawrence, and along the 

 southern and central portions of the Island of Orleans. Throughout 



