185 



notes on the geology of ardrossan and 

 Neighbourhood. 



By Walter Howchin, F.G.S., Lecturer in Geology and 

 Palaeontology, University of Adelaide- 



[Read October 10, 1918.] 



Plates XIX. to XXIX. 



CONTENTS. Page. 



I. Introduction. 186 



II. The Geological Succession. 



A. Proterozoic. 



Pre-Cambrian . 



1. Ardrossan. 2, Hart's Mine. 3, Winulta 

 Creek. 4, Weetulta, 5, Arthurton. 6, 

 Maitland. 7, Yorke Valley (eastern 

 ridge). 8, Yorke Vallev (western ridge). 

 9, Port Victoria '. ... 187-191 



B. Palaeozoic 



Upper Cambrian. 



Basal Grits and Conglomerates: — 1, Din- 

 ham's Quarry. 2, Cane's Quarry. 3, 

 Whittaker's Quarrv. 4, Winulta Creek. 

 o, East of Winulta. 6, Weetulta. 7, 

 Three miles west of Ardrossan, on the 

 Maitland Road. 8, Wundersitz's Quarry. 

 9, Maitland. 10, Yorke Valley (western 

 ridge). 11, Henderson's Quarry. 12, 

 Port Hughes ... '...... 191-195 



Upper and Middle ( Fossiliferous) Lime- 

 stones:—!, Horse Gully. 2, Pebbles on 

 Beach at Ardrossan. 3, Dowlingville ... 196-19& 



Lower Limestones (I)olomitie): — 1, Eastern 

 Scarp of Coastal Ridge. 2, Rogues 

 Gully. 3, "Sliding Rocks." 4, Mont- 

 gomery's. 5, Yorke Valley. 6, Mait- 

 land No. 1 Bore 199-203: 



C. Cainozoic 



Miocene (Fossiliferous Cherts and Glauconitic 

 Clays). 



1. The High-level Outcrops ... 204 



2. Outcrops at sea level .: 204 



Pleistocene (Fresh -water beds). 



(a) Older — High-level siliceous grits and fine 



gravel 205 



Siliceous sandstones and petrified 



wood at sea level 207 



(b) Newer — Mottled argillaceous sands of sea 



cliffs and inland 209 



Recent. 



Red clays and gravels. Raised sea beach. 



Subsidences 211 



III. General Considerations. 



1. Stratigraphical and Lithological Characteristics 215 



2. Tectonic Problems 217 



3. Peneplanation and Geological Cycles 220- 



4. River Drainage, Past and Present - 222 



