68 



CRETACEOUS FORMATION. 



(View of Hinge.) 



Fig. 119. Trigo'nia a'l&for'rnis. 



possesses peculiar characters, both in relation to the organic re- 

 mains contained in it, as well as its mineralogical relations. We 

 there find a great many shells, very remarkable for their form and 

 peculiar structure, \yhich are called hippuri'tes (Jigs. 120, 121), 

 and spheruli'tes (fig. 122). Many 

 nummuli'tes (Jig. 123), of which some 

 deposits are formed exclusively, are also 

 met with. It is not determined pre- 

 cisely to what part of the lower chalk 

 these deposits should be referred, but 



Fig. 12Q.Hippvri'tes Iw'culata. Fig. 1 2 1 .Hippvri'tfs orga'nisun* 



4. How is the chalk formation characterized in the south of Franc* / 

 What are Hippurites ? 



