III.— GEOLOGY. 



Art. XXXI. — On some Railway Cuttings in the Weka Pass. 



By Professor F. W. Hutton, F.G.S. 



\Read before the Philosophical Institute of Canterbury, 5th May, 1887.] 



Plate XIV. 



In the construction of the railway through Weka Pass, several 

 excellent sections have been made in the younger beds between 

 Waipara and the railway viaduct over Weka Creek. These I 

 examined on the 18th of November last, and the observations 

 I made are, I tbink, of sufficient interest for publication. 



Rocks exposed. 



5. After leaving the river gravels of the Waipara the first 

 cuttings on entering the pass show a series of horizontal beds of 

 silt and fine gravel ; but without any fossils that I could see. 



4. A little beyond the 42nd mile-stone from Christchurch we 

 come to a series of marine sandstones and fossiliferous con- 

 glomerates, dipping 12° S.E. by E. The junction between these 

 beds and the horizontal gravels is not exposed, but no doubt 

 the two are unconformable. This marine series is as follows : — 



Feet. 

 15. Yellow-brown sands with calcareous layers 



(about) 175 

 14. Conglomerates and brown sandstones ... 70 



13. Limestone and sandstone interbedded ... 15 

 12. Conglomerates and brown sandstones ... 40 

 11. Sandy clays and sandstones ... ... 20 



10. Shell-beds and brown sandstones... ... 50 



Total (about) ... ... ... 370 feet. 



This brings us to a gully in which stands the 43rd mile- stone 

 from Christchurch, and the next cutting to the north shows the 

 following section (PI. XIV., fig. 1), where a fault brings a brown 

 sandstone against a series of sandy conglomerates with com- 

 minuted shells, dipping 15° S.E. by E. The fault runs about 

 east and west, and does not appear to be of any great importance. 



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