301 



top is a band composed of bright green nodules with their 

 longer axes transverse to the bedding with a thickness 

 of about 10 inches. Fracture lines which cut the "Red 

 Stratum" are sharply defined by streaks of brilliant green. 

 Except for some obscure forms in the transition beds at 

 the base the zone is without fossils. The absence of well 

 defined bedding and marine fossils suggests that the 

 "Red Stratum" is not typically marine and that its depo- 

 sition may have taken place during a brief recession of 

 the sea. The thickness is 32 feet (9 m.). 



Stonehouse formation. — This, the closing formation of 

 the Arisaig series, is by far the most fossiliferous of the 

 sequence. Lithologically the first 800 feet (243 m.) 

 are not very different from the limestones of the Moydart 

 formation, but faunally there is quite a distinction, the 

 difference being largely in the abundance of large and 

 undescribed pelecypoda. An unknown thickness of what 

 appears to be the lower portion of the formation outcrops 

 on the southwest end of a hill near the head of Vamey 

 brook. The beds at this locality are flanked on both sides 

 by the Devonian red shales and the structure appears 

 to be anticlinal. The fauna is a large one and is charact- 

 erized by the abundance and large size of Chonetes novasco- 

 ticus, and an abundance of Pholidops implicata, Spirifer 

 rugaecosta, Homeospira n. sp., Grammy sia acadica, G. 

 rustica, Pterinitella venusta, P. carta, Calymene tuberculata, 

 Acaste logani, and fine large specimens of Homalonotus 

 daws oni, and in the last 200 feet (60 m.) by myriads of 

 Beyrichia piistulosa and B. aequilatera. There is a total 

 thickness of 1,075 feet (327 m.) . 



Zone I. — Deep green unfossiliferous shales with a few 

 lenticular bands of limestone. The zone rests in apparent 

 conformity on the "Red Stratum", but the contact is 

 obscure. The thickness is 33 feet (10 m.). 



Zone 2. — Grey to green impure limestone in thick beds 

 with a few beds of green and rusty purple shales and blue 

 splintery flags. The limestones are criss-crossed by seams 

 of quartz and calcite and the surfaces of many of the beds 

 are highly ripple marked. The zone ends at the mouth 

 of McPherson's brook. Fossils are not uncommon, but 

 at no place are they abundant. They are Stropheodonta 

 n. sp., Leptaena rhomboidalis, Chonetes novascoticus, 

 Atrypa reticularis, Spirifer suhsulcatus, S. rugaecosta, 

 Homeospira cf. evax, Grammy sia acadica, and Pterinitella 

 venusta. The thickness is 532 feet (162 m.). 



