26 



Between this section and the next, there is a long reach of 

 the stream, banked by no well cut sections. There are 

 numerous exposures in the bed of the stream, however, and 

 these allow an examination of the shale underlying that 

 which bears the Spirifer tullius fauna. The greater portion 

 of these "middle Moscow" shales is barren, and one may 

 search for hours without finding a single specimen. Near 

 the middle of the mass, however, about eight or nine feet 

 below the Styliolina band, occurs a thin layer containing an 

 abundance of the nearly circular brachiopod Orbiculoidea 

 media (Hall). Associated with this species are specimens of 

 Schizobolus truncatus (Hall), this being the lowest position 

 in the Hamilton strata, in which this species has been found. 



As we approach the bottom of the Moscow shale, fossils 

 become abundant again, the first to do so being the trilobite 

 Phacops rana (Green), of which very good and large speci- 

 mens may be obtained. These lower Moscow beds should 

 be explored when the water in the stream is low, the shale 

 in the stream bed being much more accessible than 

 that in the bank at Section 5. Just before reaching this 

 latter section, the stream descends over the hard Encrinal 

 limestone bed, which separates the Moscow shales from the 

 Hamilton shales proper. 



It is above this fall, in the bed of the stream, that the 

 lower Moscow shales are best exposed. The fossiliferous 

 portion comprises about five feet of the shale, which is 

 characterized by an association of species, differing from 

 that at other levels. The robust, short winged, sparingly 

 plicated Spirifer called in the old reports S\ zigzag (Hall) 

 from the zigzag surface striae, but the correct name for 

 which is S. consobrinus ( D'Orb. ) is entirely restricted to 

 these shales, and gives its name to the fauna. Besides the 

 type species, the Spirifer consobrinus fauna comprises a 

 large number of species which are common only at this level, 

 while a few are entirely restricted to it.* In the shale 



I Ot a complete list of the fossils of this fauna see the author's paper on the 

 itinas "i the Hamilton Group, etc." 



