50 Later Extinct Floras of North America^ 



the JRhamnacece, and more of the aspect of the leaf of a Laura- 

 ceous tree, but the numerous parallel Bide-nerves, terminating 

 all in the margins, form a character which the Laurels never 

 have. 



Of described species, it most resembles Weber's I*. />,<■!,,,,'>. 

 (Palseontographica ii. S. 204, T. 23, fig. 2), but differs from it 

 in having an ovate, lanceolate form, and the nervation is a lit- 

 tle more crowded. 



Formation and Locality. Miocene Bandstone. Belmont, 

 Colorado. (Miss Kate Haymaker.) 



IS Ii a in ii i to* coiicinnus (n. sp.) 



Leaves petioled, long ovate, acute, rounded at the base, coarsely 

 and nearly equally mucronate-dentate ; nervation pinnate, remark- 

 ably precise and parallel throughout; medial nerve straight ; lat- 

 eral nerves, 9-10 pairs diverging at an angle of about 20°, slightly 

 arched upward, parallel among themselves, basilar pair reaching to 

 margin below the middle of the leaf, Bending off each about 8 short, 

 simple, slightly curved, parallel branches to the dentations of the 

 -lateral margin; superior lateral nerves simple, or once forked 

 at the summit; tertiary nerves very numerous, simple, parallel, 

 connecting the lateral secondary nerves and the branches of the 

 basilar nerves nearly at right angles. 



These beautiful leave- are so definite in form and structure, 

 and so perfectly preserved, that we should have no difficulty 

 in referring them to their appropriate genus, if we could find 



among living trees their precise generic counterpart, but up to 



the present time I have not been able to satisfy myself thai they 

 are generically related to any living plants. The nervation is 

 in gome respects \<i\ like that of B&rchemia ; e.g. /!. volubilis, 



the "Supplejack" of our Southern States. Nowhere else do 



1 remember to have -ecu the Baine parallelism of the secondary 



and tertiary nerves, but the -••nation of the margin is coarser 



than in any of the Rhamnacea with which I am acquainted, 



and the development of the basilar pair of lateral nerves is 



much greater than in Berchemia. This latter character is 



