39 



overgrown with delicate Bryozoa and Aulopora corals, 

 which furnish an additional incentive for collecting them. 



A large number of concretions occur in this lower shale, 

 among which the horn-shaped forms with smooth slicken- 

 sided exterior are characteristic. These are often mistaken 

 for organic remains, chiefly cup corals, and are prized as such 

 by the inexperienced collector. An axis or core of iron 

 pyrites will usually be found as the nucleus of these concre- 

 cretions. Frequently the strata above and below, as well as 

 on the sides, appear crowded out of position, as if by the 

 growth of the concretion. As before noted, however, this 

 crowded appearance is probably due to the settling down of 

 the strata around the resistant body. 



A few feet below the layer bearing the Athyris spiritbroides 

 (Eaton), pelecypods occur plentifully. A large num- 

 ber of species have been obtained, many of which have not 

 been noticed elsewhere in this region. At the base of the 

 cliff, near the mouth of the "corrv " Liorhvnchus multicostus 

 Hall again occurs in abundance in some concretion bearing 

 beds. Another concretionary layer containing A. spiriibr- 

 oides (Eaton) occurs twenty feet below the Encrinal lime- 

 stone. Throughout the exposed portion of the shales, 

 fossils occur in considerable number and variety. Brachio- 

 pods always predominate, the most abundant being 

 Spirifer tnucronatus (Conrad). Good specimens of the 

 trilobite Phacops rana (Green) are occasionally found ; but 

 on the whole, only the smaller species of organisms are 

 abundant. Thus, Chonetes lepida Hall, and Amhocoelia 

 umhonata (Conrad), as well as the little Pholidops hamil- 

 toniae Hall, are abundantly scattered through the shales. 

 Liorhvnchus multicostus Hall is common in the lower ten 

 or fifteen feet. 



About twenty-five feet below the Encrinal limestone occurs 

 a thin argillo-ealcareous bed, less than two inches thick. 

 This contains large numbers of Modiomorpha subalata 

 (Conrad), a characteristic Hamilton pelecypod, and one 



