PONDICHERRY— PRODUCTUS. 99 



The name was used by Hayden afterwards in the same sense 

 (Geog. and Geol. of the Him.. Part IV, 234, 1908) for the 

 upper of the two series composing his Kanawar system in Spiti. 



ProductUS limestone. — As for many years the only conspicuous 

 limestone with Productus in India was that of the Salt Range 

 in the Punjab, the name gradually accpiired a technical value as a 

 stratigraphical term ; but with the more recent discoveries in 

 the Central Himalaya, the Shan States and elsewhere the term 

 now recpures its full expression, Productus Limestone of the 

 Salt Range, to be understood. The name was used by W. Waagen 

 in his paheontological memoirs (Pal. Ind., Ser., XIII, Part I, 7, 

 1879 et. seq) to replace the term " Lower Limestone " used by 

 A. B. Wynne {Mem., Geol. Surv., Ind., XIV, 69, 1877), who re- 

 garded the beds as Carboniferous in age. Waagen (Pal. Ind., Ser. 

 XIII, Vol. IV, Part 2, 234, 1891) concluded that the Productus 

 Limestones of the Salt Range were mainly Permian in age, the 

 lowermost beds being correlated with the Artinskian stage, while 

 the topmost (Chidru) beds were regarded as passage between the 

 Permian and Triassic. Waagen divided the Productus Limestone 

 as follows : — 



( 7. Chidru beds. 

 Upper . . . < 6. Cephalopoda or Jabi beds. 



(_5. Kundghat beds. 



("4. Kalabagh beds. 

 Middle . . . ] 3. Virgal beds. 



(-2. Katha beds. 



") 1. Ami) beds and 



5 Upper Speckled Sandstone. 



F. Noetling {Neues Jahrb., XIV, 369, 1901) considers that the 

 Lower Productus beds are even younger than the Artinskian of 

 Russia, and correlates even the underlying sandstones and glacial 

 boulder-beds with the Rothliegende, while the Productus Lime- 

 stone is referred to the Thuringian stage of the Zechstein, with a 

 gradual passage up into the Trias through the Chidru beds. 

 Th. Tschernyschew (Mem. du Com. Geol. Russ., XVI, No. 2, 1902, 

 and Rec., Geol. Surv., Ind., XXXI, III, 1904) argues strongly in 

 favour of regarding the Productus Limestone as mainly Carboni- 

 ferous. The Amb beds he correlates with the Omphalotrochus 

 horizon of the Ural, while the Katha, Virgal and Kalabagh beds 

 between them are equivalent to the Cora and Schwagerina 



h 2 



