97 



beds. Characteristic species are Dalmanites (Probo- 

 lium) biardi, D. perceensis, Phacpos logani, Chonetes 

 canadensis, Chonostrophia complanata, Spirifer arenosus, 

 S. murchisoni, Lepioccelia fiabellites, Rensselaeria ovcides. 



No other trace of the formation and fauna represented 

 by Perce Rock is to be found in this vicinity except in 

 the Murailles or sea cliffs which lie beyond the North 

 Beach and face the Mai bay. The grey headland of 

 Cape Barre with which the Murailles begin, is followed 

 by a faulted and overthrust mass of highly coloured strata, 

 dipping S.E. 20° and abutting against the Cape Barre 

 strata, containing, sparsely, the fossils of the Perce Rock 

 strata. These inclined strata rise to the high peaks of 

 the Murailles but their tops are there coated unconformably 

 by a layer of the limestone conglomerate of the Bona- 

 venture series. 



The observer will not fail to notice the colony of water- 

 fowl nesting on the green capped top of the Isle perce. 

 This settlement is composed only of the Herring gull 

 (Larus argentatus) and the Cormorant (Phalacrccorax 

 carbo), an association which is repeated on the cliffs of 

 the Forillon peninsula 17 miles (30 km.) to the north 

 (see note beyond on the bird colony of Bonaventure 

 island). 



Perce Rock is composed entirely of Lower Devonian lime- 

 stones standing nearly vertical (dip 8o° S.E.) and highly 

 tinted with iron yellows, reds and purples. Its strata are 

 seamed with calcite veins of white, red and deep brown, 

 often with interesting crystallizations. The combination 

 of rock colours with the green cap of verdure produces strik- 

 ing effects which vary with every change in atmospheric 

 conditions and the position of the sun.* 



Cape Barre. — This is the southern point of the Murailles, 

 bounding the North Beach. Its strata are thin, sandy, 

 blue grey shale and limestones dipping 30°-40° N.E., 

 the red rocks of the Perce massive being faulted against 

 them. These rocks contain only a few fossils, all of 

 Lower Devonian type (Spirifer cf. modestus, Leptostro- 

 phia oriskania, Conularia cf. lata), the most significant 

 being a species of the trilobite Dicranurus (D. limenarcha) 

 of which only two other species are known, both from the 



*For an account of the history of Perce Rock in the records of Gaspe, of its 

 changes in form, rate of degradation, total fossil contents, etc., see Clarke [9]. 



35063—7 



