107 



2. — Northward from the above locality several shallow 

 quarries were opened in the fields for the production of 

 stone from the encrinal layer (No. 3). These shallow pits, 

 long since abandoned, have proved a rich collecting ground 

 for the corals of the overlying shale. This locality has 

 also yielded many examples of the rarer blastoids for which 

 the Thedford section is noted, e.g. Eleutherocrinus casse- 

 dayi Shumard and Yandell, Codaster canadensis Billings, 

 and Nucleocrinus elegans Conrad. 



3. Hamilton Section at the Brickyard. — The 

 exposed clay surfaces at the brickyard afford excellent 

 collecting ground. Upstream near the first important bend, 

 the black Leiorhynchus shale (No. 2), at the base of the upper 

 shale division is about 14 feet (4-2 m.) above the creek bed. 

 The coral shales are the highest strata exposed and from 

 them come most of the fossils that make the brickyard 

 a noted collecting ground for numerous species of Hamilton 

 corals. Abundant and well preserved examples of the 

 various species of Heliophyllum, Cystiphyllum, Favo sites, 

 Acervularia, etc., may be found here. Many of the 

 other fossils of zones 1, 2, 3 and 4 may also be obtained. 



Good exposures with excellent collecting are to be 

 found farther down stream where the spring freshets 

 have cut gullies in the soft strata of zone No. 4. The inter- 

 esting coral, Microcyclus discus Meek and Worthen, 

 occurs at this horizon associated with Ancyrocrinus and an 

 occasional Pentremites. 



4. Hamilton Section of the Aux Sables River. — 

 An excellent section exposing the strata from near the base 

 of zone No. 1 to the top of zone No. 6 extends up the 

 branch stream which enters the Aux Sables river a short 

 distance below the power house (Power glen or Rock 

 glen). The difference in elevation between the mouth 

 of the stream and the top of the limestone above the falls 

 is 66 feet (10 m.). 



About 100 yards (91 m.) below the falls, right at the 

 waters edge, is a thin bed of dark argillaceous limestone 

 containing species of Platyceras associated with Arthro- 

 acantha fragments. Small examples of Schucherlella are 

 also present. About 29 feet (8-8 m.) above the mouth of 

 the brook, the six inch bed of black shale occurs, marking 

 the top of the lower shale division (See No. 2 of section). 

 Leiorhynchus laura is plentiful in this layer. The lime- 

 stone immediately above furnishes the fossils common in 



