355 



The strata of the area of the so-called Intermediate 

 group indicated on the accompanying map, may, as 

 already stated belong in part to the Millstone Grit. What 

 appears to be the lowest member of the Intermediate 

 group holds as a characteristic member a very considerable 

 thickness of red strata that in composition vary from an 

 argillite to a limestone, are generally of a bright, brick- 

 red colour but in many places are splotched or banded 

 with green. With these rocks are associated reddish sand- 

 stones and conglomerates and, perhaps, grey and dark 

 grey limestones and siliceous beds. 



A second division of the Intermediate group, younger 

 than the above, consists of coarse, heavily bedded conglo- 

 merates and sandstones overlain by dark grey thinly 

 bedded limestones which in places, as near Hillsborough, 

 are capped by a considerable volume of anhydrite and 

 gypsum. 



A third, still younger member of the Intermediate group 

 is made up essentially of red conglomerates and sandstones 

 succeeded by red and green argillites and argillaceous 

 limestones. 



The total thickness of these three divisions of the 

 "Intermediate group" must surpass several thousand feet. 

 The strata in places lie with high angles of dip; in other 

 localities they are nearly horizontal, and in such cases 

 different divisions may appear to succeed one another 

 conformably, as if without a break, although there is 

 indirect evidence to indicate that prior to the deposition 

 of each succeeding division, the strata of the immediately 

 underlying division had been eroded in no inconsiderable 

 degree. 



The Albert series is the oldest of the Carboniferous 

 system in the district. This series consists of a group of 

 thinly bedded, usually dark coloured slates, calcareous 

 slates, limestones and sandstones. Interbedded with 

 these, whether or not at more than one general horizon has 

 not yet been determined, are slates relatively rich in hydro- 

 carbons and of a distinctive appearance. These, so-called, 

 oil-shales when retorted yield varying amounts of crude 

 oil and nitrogen — about 27 to 56 imperial gallons of crude 

 oil, and about 30 to 112 pounds of ammonium sulphate 

 per ton [3, part I, p. 17]. In these oil shales and associated 

 beds, in places, are numerous remains of fishes of the genus 

 Palaeoniscus. From the Albert series as developed in the 

 35063— lO^A 



