166 W. A. Bell — Mississippian Formations of 



of deposition. The subzone terminates with a thick band 

 of anhydrite and gypsnm. 



Subzone B is characterized by the presence of two 

 limestones that are extremely fossiliferous, and as they 

 outcrop in the vicinity of the town of Windsor, they afford 

 a rich collecting ground. The lower or Maxner limestone 

 is about 80 feet in thickness, the upper or Miller limestone 

 about 35 feet, the tAvo being separated by a second band 

 of gypsum. The fauna is common to the two limestones, 

 but the association is somewhat different. The Maxner 

 limestone is characterized particularly by the abundance 

 of Diodoceras avonense in its upper portion and by the 

 great profusion of individuals of species of Dielasma and 

 Composita in which the brachidia are excellently pre- 

 served within the hollow interiors. The Miller limestone 

 is characterized by an abundance of Aviculopectens, bry- 

 ozoans, and productids. 



Subzone C is best exposed on the Avon estuary at Wind- 

 sor in the neighborhood of the bridges. The section, how- 

 ever, is broken by a number of important faults. The 

 lower part of the subzone has frequent oolitic, algal, and 

 sandy dolomitic beds that are sparingly f ossiliferous, but 

 in the upper part some 20 feet of platy blue limestone fur- 

 nishes abundant Martinia and Productus. 



Subzone D has a thick g^^osum member at its base, in 

 which are a number of thin calcareous seams crowded 

 with ostracods and with the foraminifer Nodos'niella. 

 The upper beds are best exposed at the mouth of Kennet- 

 cook river, where 100 feet of thinly bedded blue-grey 

 limestones carry a fauna which is more normally marine 

 than any which preceded it. Cup corals become abund- 

 ant here for the first time, there is a greater variety of 

 brachiopods, and the molluscs are mainly confined to the 

 Bellerophontidse. 



The following generalized lithological section illus- 

 trates the rhythmic recurrence of mud deposition with 

 chemical and organic deposits : 



D. Kennetcook limestone 100'+ 



Gypsum and anhydrite with Nodosinella bands. 



Ked shale, etc. 

 C. Avon River limestone l:5'-t- 



Gypsum? and red shale. 



Dolomitic and calcareous shales and sandstones, 

 oolites, algal and Modiola bands. 

 B,. Miller limestone 35' 



