PEALE.] 



EESUME— PALEOZOIC SILUKIAN. 



615 



The letters in this section correspond with those given in the illustra- 

 tion of sections across the Portneuf Range in Chapter lY. 



From the position of these beds in relation to those of the section 

 (No. 20) of Station 76, 1 am inclined to consider them as at the base of 

 the Canadian, or perhaps all the equivalent of the Potsdam, although 

 the section is somewhat like the top of Section IsTo. 22. I think Mr. St. 

 John is inclined to refer the base of the section to the Huronian. In 

 the following section the double hne separating the two portions indicates 

 the line of greatest obscurity in the sequence. 



The Ust of fossils following the section giVes the localities of un- 

 doubted Silurian rocks throughout our district. I did not recognize any 

 Upper Silurian. 



Silurian section. 



H 



O 



Very dark-green chloritio schists, containing quartz and serpentine 

 seams and interlaniuiated 'bands of metamorphosed argUlaceons 

 slates, and a band of pink quartzite 200 feet thick. 



Limestones. 



Eed quartzites and quartzitic sandstones, with conglomeritic and 

 shaly layers. 



Dark quartzites with interlaminated slates. 



Silvery and steel-gray micaceous slates. 



Olive-green and gray chloritic slates and indurated clay slates. 



Pink and -white quartzites, conglomeritic at top ■with thtu 

 layer of limestone at the base. 



Blue limestones, generally laminated with alternations of 

 greenish sandstones and shales and siliceous slates. 



Blue and gray limestones, with characteristic Quebec fossils. 



+ 



+ 



+ 







Organic contents. 



Fossils characteristic of the Quebec Group were found in our district 

 in 1872, by Professor Bradley. The finding of these fossils marked 

 the first identification of the group in the Eocky Mountains. 



The following list of fossils near Malade City is quoted from the report 

 for 1872 (p. 464): 



Camerella calcifera BiUiugs. 



Orthis hippoUte Billings. (?) 



Orthis like 0. electra Billings. 



Euomplialus (?) trocMscus Meek. 



JEuomphcdus (?) rotuli/ormis Meek. 



Uuomphalus or Ophileta. 



