204 



1. The High-level Outcrops. The top of the banks on the 

 northern side of Horse Gully are capped by these Miocene 

 cherts, especially the prominent knoll of the Sheaoak Hill, 

 which is included in the section given on page 196. Similar 

 outcrops occur at intervals on the higher ground, going 

 northward; and after crossing the Maitland road, 1 mile 

 from Ardrossan, surface stones belonging to these beds cover 

 a considerable area in the neighbourhood of Dinham's 

 quarries, where a fine example of the rare fossil, Pleuroto- 

 marla, was obtained. These high-level occurrences extend in 

 a north and south direction for a distance of about 3| miles. 

 At Horse Gully the fossiliferous cherts rest on the Cambrian 

 pteropod limestones, while at Dinham's they rest on the 

 Cambrian basal grits. 



2. Outcrops at sea level. At Rogues Point, about 5 

 miles to the southward of Ardrossan, the fossiliferous Miocene 

 beds make their appearance on the beach, and from thence, 

 for about 2 miles to the southward, they make an almost 

 continuous feature along the beach. At the first small point 

 in the sea cliffs, to the southward of the old jetty at Rogues 

 Point, highly siliceous Turritella beds occupy the beach and 

 slope upwards to the base of the cliffs, which are formed of 

 recent deposits. At a quarter of a mile distance, in a 

 southerly direction, near Meninie Hill, there is another ex- 

 posure of these beds, highly silicified, and situated at sea 

 level. A little further south, near a small creek, the Tertiary 

 beds make a cliff 20 feet in height and are divided up into 

 hard and soft layers. The silification has followed certain 

 horizons where we find Turritella cherts forming: beds about 

 a foot in thickness, and these are separated by glauconitic 

 clays of somewhat greater thickness, which are coloured green 

 or red, according to the measure of oxidation to which the 

 glauconite has been subjected. These glauconitic clays 

 appear to be unfossiliferous, but scattered through them are 

 cherty concretions and bifurcating cylindrical forms contain- 

 ing impressions and casts of fossil shells. 



As the beds pass more to the southward they have a 

 low dip to the south, and the mottled clays, which have 

 such a striking development in the cliffs near Ardrossan, put 

 in an appearance overlying the fossiliferous beds, attaining 

 a thickness in the cliff face of 20 feet. Before reaching the 

 next small projecting point in the cliffs, at the northern 

 fence of Section 49, the consolidated freshwater sands replace 

 the mottled clays and rest immediately on the fossiliferous 

 Miocene. 



To the southward of the last-named point the Miocene 

 beds roll slightly, in long curves, with a maximum dip of 



