22 



brian upland, most of them have cut deep gorges on their way to the 

 main stream, and some good sections of the Cambrian rocks have been 

 exposed. The best of these for the Coldbrook and Etcheminian 

 terranes is that of Dugald brook. (See preceding page.) 



Section on The Etcheminian terrane is exposed in the gorge below the falls at 



Dugald brook. _ . , . . . ., .,..,, 



Dugald brook in a series ot vertical beds horn the base to the summit 



of the terrane. The measures are cut at right angles to their course 

 which is N. 60 (inag.) and present the following upward succession. 



DIVISION 1. In all 122 feet. . 

 Assise a consists of 



1 5 feet dark purple amygdaloid and bright red slate Fossils. 

 10 feet dark purplish-gray trap and ash-rock. 

 18 feet soft purplish-red shale. 

 Assise b consists of 



18 feet dark purplish-gray finely crystalline trap. 

 10 feet measures concealed (shales ?) 



6 feet gray quartzites. Fossils in sand and clay seams at the top. 

 Assise c consists of 



21 feet dark gray shale. Fossils at the middle of the assise, in 

 soft layers. 



Assise d consists of 



21 feet compact dark gray sandy shale. 



Assise e consists of 



3 feet gray shale with seams of greenish-gray sand and lavender 

 ' gray clay. Each of these assises is fossiliferous. 



Notes on thejossils of Division 1. 



Those of Assise a are found in the bright red shale. They are very 

 much corroded and therefore obscure, a Hyolithes, a Lingulella and 

 worm-burrows are recognisable. 



Fossils of ASSISE b. The matrices of the fossils are seams of greenish gray- 



bivisbn'i. weathering sand, in layers of lavender gray, rusty- weathering fine 

 shale. The grains of the sandy layers are mostly of pellucid and of 

 green quartz. Some grains are of a bright copper-green colour. There 

 are numerous minute fragments of red feldspar (and of red felsite?) 

 not kaolinized. There is a pale green (magnesian?) deposit in places 

 among the sand grains. The sand is mixed with numerous fragments 

 of the shells of Brachiopods and a few Ostracods. 



