274 ROYAL SOCIETY OF CANADA 



the same inclusions namely, — liornstone, red and white sandstone, lime- 

 stone, granite, also grains of quartz and felspar. (See fig. 20.) 



A thin section of the rock, shows the paste to consist largely of ai 

 carbonate having brilliant polarisation, indicating a high iron or mag- 

 nesia composition. The definite clastic outlines of the quartz and felspar 

 makes it evident that they do not come from the igneous cementing 

 material. The only minerals which it is certain are related to the 

 original cement are, — apatite, perovskite, iron ore, melilite, hydro- 

 nephelite and analcite. The apatite is acicular, forming a thick mat. 

 Perovskite is extremely abundant in octahedra. Iron ore is not abundant 

 and is chiefly found as a rim to the perovskite. The melilite is very 

 plentiful and is definitely recognisable. Intergrown with the carbonate 

 is a mineral having low refraction, dull polarisation and wavy extinction, 

 — probably hydronephelite. A similar mineral, but having still duller 

 polarisation and without wavy evtinction is considered to be analcite. 



Near Cote St. Paul. 



The material from near Cote St. Paul cannot be designated an 

 occuiTence since it takes the form of a boulder found in the soil removed 

 during the excavation of the aqueduct. 



The boulder is a rounded block chiefly of Devonian limestone, about 

 one cubic foot in volume ; adhering to one side, however, is a lump of the 

 typical local breccia. (See fig. 21.) The boulder has evidently come 

 from the contact of the limestone with the breccia. The direction of 

 glaciation would indicate that it came from Ste. Helen's Island, which 

 lies about five miles to the north-northeast. The fossils in the limestone 

 are very numerous and are interesting since they belong to the same 

 horizon as the most recent of the limestone inclusions of Ste. Helen's 

 Island. The palaeontology is discussed at length by Dr. H. S. Williams 

 in his paper. 



Thin sections show fragments of fine grained sandstone, peridotite, 

 granite, quartz and felspar, in a paste consisting of biotite, olivine, 

 augite, apatite, pyrite, magnetite, perovskite, melilite and hydronephelite. 

 The peridotite is largely composed of olivine, with less abundant augite, 

 biotite, hornblende and magnetite. The granite is represented by a mass 

 of alkalai felspar and quartz, no mica or hornblende showing. The 

 quartz and felspar grains are of the same order of size and otherwise 

 similar to those of the granite; they are undoubtedly clastic and so are 

 very probably derived from the granite. 



The biotite occurs in well formed phenocrysts in considerable 

 amount. Olivine is now represented by a number of yellow spots com- 

 posed of serpentine and bastite, filling outlines characteristic of olivine 



