506 GEOGRAPHICAL ZOOLOGY. [i>art iv. 



.Family 6. — BELEMNITID^. Fossil. (6 Genera, 100 



Species). 



Distribution. — Lias to Chalk in Europe, India and North 

 America. 



Order II.—TETRABRANCHIATA, 



Family 7.— NAUTILID^. (1 Genus, 3 Species, Living; 4 

 Genera, 300 Species, Fossil). 



Distribution. — Indian and Pacific Oceans ; ancl the fossil 

 species from the Silurian Period to the Tertiary, in all parts 

 of the world. 



Family 8.— ORTHOCEEATID^. FossU. (8 Genera, 400 



• Species). 



Distribution. — Lower Silurian to Lias. 



Family 9.— AMMONITID^. Fossil. (14 Genera, 1100 



Species). 



Distribution. — Upper Silurian to Chalk. Found at 16,000 

 feet elevation in the Himalayas. 



