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some blocks of the Mississippian conglomerate have been 

 included in the diabase. By ascending the brook the Devo- 

 nian shales as well as the Mississippian conglomerate 

 and the amygdaloid which lies just above the base of the 

 latter may be seen. For the first 250 yards (228 m.) 

 east of McAra's brook the shore is formed almost wholly 

 of amygdaloid. There is no beach and the top of the cliff 

 must be followed. At McAra's boat landing, where 

 descent can be made to the beach, the amygdaloid is 

 succeeded by the McAra's Brook conglomerate which 

 then forms the shore for about 125 yards (114 m.) where 

 it is succeeded by the diabase dyke at the top of the 

 Silurian. It is quite easy here to make a representative 

 collection of fossils from the Silurian red limestones and 

 shales. At the mouth of Stonehouse brook it is possible 

 to obtain entire specimens of the trilobite, Homalonotus 

 dawsoni. 



From Stonehouse brook to beyond the "Red Stratum" 

 there is no beach and this portion of the Silurian section 

 must be studied from the top of the cliff. The "Red 

 Stratum" and the overlying green shales are without 

 fossils, but the limestone which underlies the former and 

 forms the point to its east contains many specimens of 

 a brachiopod resembling Eatonia medialis. Beyond 

 this point is McDonald Brook cove wherein the Moydart 

 rocks form low cliffs. The succeeding point is also formed 

 of Moydart rocks, but in the cove to the east the formation 

 comes to an end. At the western end of this cove descent 

 can be made to the beach which, with few interruptions, 

 extends to Arisaig point. The upper beds of the McAdam 

 formation form a serrated cliff from which it is quite easy 

 to collect many fossils, of which few are well preserved. 

 The point east of McAdam Brook cove is formed of 

 shales, which are full of pelecypod casts, and nearly 

 unfossiliferous limestone. The eastern side of the suc- 

 ceeding cove does not offer good exposures, but from a 

 few interstratified beds of limestone which project through 

 the beach debris it is possible to collect large individuals 

 of Atrypa reticularis. The slopes above this cove 

 show the elevated terraces in a fine state of preservation. 

 At its eastern horn is Black point, a headland formed 

 of glacial gravels, on the eastern side of which the McAdam 

 formation ends, being cut off by the fault which has 

 elevated the Ross Brook shales and placed them on a level 



