172 GEOLOGY AND PETROGRAPHY OF CLARENCETOWN-PATEESON DISTRICT, i., 



matrix, which is only found unweathered in a few instances, is seen in thin 

 section to be a potash-rhyolite. 



Just to the east of the line of section in portion 52, Parish of Wilmot, this 

 unit is underiain by a reddish tuff, which consists of fragments of quartz, albite 

 and orthoelase and pieces of pitehstone and keratophyre, the whole modified by 

 secondary silica. 



The volcanic conglomerate, described above, is then succeeded by normal 

 red tuffs, which unfortunately are unfit for microscopic examination. These 

 fonn the topmost member in the long series detailed above, and following them 

 one can trace the sequence into the Glacial Stage, the distinctive conglomerate 

 at the base of that Stage being met with in the headwaters of McManus' and 

 Caswell's Creeks. 



The Mt. Gilmore Section shows the following succession : 



Thickness in Feet 



Hornblende-andesite 80 



Tuffs with occasional pebbles 150 



Hypersthene-andesitic pitehstone 50 



Conglomerates and tuffs . 80 



Sodi-potassic rhyolite 45 



Conglomerate 75 



Biotite-quartz-keratophyre 150 



Conglomerate 25 



Biotite-quartz-keratophyre 30 



Conglomerate and tuff - . 105 



Lava intermediate between rhyolite and dacite 150 



Conglomerate with a band of keratophyric tuff 320 



Dellenite-toscanite lava 400 



Tuffs with a band of felsite - . . 80 



Dacite with spherulitic inclusions 60 



Tuffaceous conglomerate . . 45 



Dacite 70 



Conglomerate 150 



Red amygdaloidal potash-rhyolite 60 



White felsite 100 



Conglomerate 50 



Keratophyre with fine-grained upper surface 90 



Conglomerates . . . 90 



Potash-rhyolite 40 



Conglomerate with quartzitic contact margin . . . . . . 80 



Dacite ■ 50 



Potash (?)-rhyolite 50 



Tuffs with conglomerate bands . • 130 



Volcanic conglomerate 50 



Tuffs .. .. 45 



Total Thickness 2900 



The La II glands Section. (C-D on Map). Text-fig. 3. 



The succession of volcanic rocks on the Langlands Estate may be most com- 

 pletely studied along the line C-D. A few of the horizons shown in Text-fig. 3 

 do not occur on the actual line of section, but their stratigraphical positions 

 have in all eases been clear, and they are therefore incorporated into the section, 

 which is therefore somewhat generalised. 



The hypersthene-andesite-glass may be seen amongst the alluvium of Tumble- 

 down Creek, on its right bank, the fiow being apparently thin. A thick mass 

 of conglomerate with some important bands of tuff overlies the pitehstone, the 

 outcrops being in places obscured by alluvium. The first lava to succeed the 

 pitehstone is then a lavender-coloured rhyolite in which the phenocrysts are 



