system. 



Park. — The Loicer Mesozoic Bocks of New Zealand. 393 



relations of the Trias and associated rocks, and to establish a 

 classification that shall be a safe standa,rd for the correlation 

 and grouping of strata throughout the colony belonging to the 

 Lower Mesozoic and Upper Palaeozoic periods. The nomen- 

 clature I have adopted is as follows: — 



Jurassic ... 1. Mataura series. 

 Triassic ... 2. Shaw's Bay series. 



{a.) Glavigera beds. 

 -p, , . (b.) Mytikts probleviaticus and 



Hokonui^ ]\2onof.is salinaria beds. 



(c.) Trigonia beds. 

 (d.) Halobia lommeli beds. 

 (c.) Spirifervna beds. 

 (/.) Nugget Point plant beds. 



This classification is an extension of that formulated by 

 Captain Hutton in 1899, and a modification of that adopted 

 by the Geological Survey in 1878. 



The boundary between the Oreti and Kaihiku series of the 

 Geological Survey is not very well defined, and in some places 

 these series seem to cover the same set of beds. In other 

 places, as in Nelson, the Wairoa series includes beds that are 

 elsewhere included in the Oreti and Kaihiku series ; and the 

 Clavigera beds that in the Hokonui disti-ict constitute the 

 Otapiri series have in Nelson been referred by the Geologi- 

 cal Survey to the Kaihiku series.''' 



The Wairoa series, as defined by Sir James Hector in his 

 " Outhne of New Zealand Geology," 1886, pp. 72-74, ap- 

 parently includes all the beds that are elsewhere considered 

 to constitute the Oreti and Kaihiku series of the Geological 

 Survey. 



(f.) Nugget Point Plant Beds. — These are the lowest beds 

 exposed at Nugget Point and Eighty-eight Valley, and they 

 are correlated with the Mount Potts plant beds, which are 

 also the lowest rocks exposed in the upper Eangitata. At the 

 two former places they underlie the Spiriferina (Psioidea) 

 beds ; and at Mount Potts the Tank Gully plant beds appear 

 to underlie the shell beds at Rocky Gully. 



At Nugget Point the plant-remains are broken and indis- 

 tinct ; at Hunt's farm, in Eighty-eight Valley, they are 

 broken, but distinguishable ; while at Tank Gully tlae beds con- 

 tain a varied and well-preserved flora. As I have just men- 

 tioned, the Tank Gully beds seem clearly enough to underlie 

 the shell beds at Rocky Gully. They ai-e readily accessible, 

 easily found, and occur in such a position that their outcrop 

 cannot be obscured or obliterated by cultivation or the con- 



* Reps. Geol. ExpL, 1878-79, p. 117. 



