34 



fauna, which is by far the richest of any of the faunas of this 

 region. 



The most fossihferous bed in this fauna is the one exposed 

 at the very base of Section 5, about a foot below the 

 Encrinal hmestone. This bed has l)een called the Demissa 

 bed, from the fact that the brachiopod Stropheodonta 

 demissn ( Conrad ) occurs in it in great numbers and is prac- 

 ticalh^ restricted to it. It has furnished more than sixty 

 species of fossils, though its total thickness is not over four 

 inches. It mav be explored at low water continuously along 

 the base of the cliff, as well as in the shallower portions of 

 the stream below the fall. The occurrence oi Stropheodonta, 

 especialh' S. demissa (Conrad) and the large wS. concava 

 Hall, as well as large nxnnbers of Spiriters, including the 

 large and robust S. granulosus (Conrad), make it con- 

 s])icuous. This latter species occurs also in considerable 

 nundjers in the Encrinal limestone, but it has not been 

 observed in the Moscow shales. It does not occur, at 

 Eighteen Mile Creek, in the shales below the Demissa bed.* 



Near the lower end of the section occurs an oblique thrust 

 fault, which has brought up about a foot of the shale under- 

 lying the Demissa bed. The shearing plane passes obliquely 

 upwards from left to right, (as seen from the opposite bank). 

 The inclination from the horizontal is 2-4°, thus giving the 

 fault a hade of 66°. The fault is of interest as indicating a 

 compressive force, the same probabh' which caused the 

 anticlinal fold at Section 3, and the other thrust faults to be 

 noted later. 



Section 6 (C). 



Platk XI. 



This section is cut in the left bank of the stream and ex- 

 tends in a general north and south direction. Its height is 

 about sixtv-t\vo feet above the stream bed, and its total 



*For a list of the fossils in the Demissa bed, see "Faunas of the Hamilton Group," 

 etc. They are all included in the descriptions iu Part H. 



