252 



The section is as follows, from the top downward: — 



Pennsylvanian system. 



Productive Coal Measures. — Sandstones and 

 shales with a number of workable coal seams 

 and several thinner ones. Plant remains are 

 abundant in the series; upright tree trunks 

 are not infrequent in the shales, and roots and 

 rootlets in position are abundant. Anthra- 

 comya and ostracods are abundant in the 

 black shales associated with the coals and 

 much the same fauna is also found sparingly 



in an occasional thin bed of limestone i,970 ft- 



(600 • 5 m.) 



Millstone Grit. — A massive, yellowish to grey, 

 coarse, feldspathic sandstone with numerous 

 pebble beds in the middle and lower portions ; 



occasional thin beds of coal occur 3,625 ft. 



(1,105 m.) 



Point Edward formation. — (Name new; form- 

 erly considered the top of the "Limestone 

 series.") Alternating sandstones and shales, 

 which are predominantly red or purplish in 

 colour. The sandstones are characterized by 

 cross-bedding produced by the translation 

 ripple. Occasional limestones occur which 

 with the shales are sometimes mud-cracked. 

 Gypsum beds occur occasionally. A fauna 

 consisting almost wholly of Leaia, a few 

 species of Anthracomya and ostracods occur 

 in the beds of grey shale. This fauna is also 

 found, in part at least, in the Riversdale and 

 Union formations near Truro. The Point 

 Edward formation is correlated in a general 

 way with those formations. According to 



Robb, the thickness is about 700 ft. 



(213 m.) 

 Mississippian system. 



Windsor series. — Marine limestones and grey or 

 red shales with occasional sandstones. This 

 formation is not so well developed or so well 

 shown in the Sydney section as it is in other 

 localities on Cape Breton island. The total 



