ART. 1. PKIMATES OF THE FORT UNION GIBLEY. 37 



EXPLANATION OF PLATES. 



Plai^ 1. 



(All figures about 4 times natural size.) 



Page. 



Fig. 1. Palaechthon alticuspis Gidley. Genus and species new. Genotype. 



Portion of a right lower jaw. No. 9532 U. S. Nat. Mus. Coll G 



2. Paromomys maturus Gidley, new genus and species. Paratype. Por- 



tion of a right lower jaw, outer-side view; 2a tooth-crown view. 



No. 9545 U. S. Nat. Mus. Coll 3 



3. Paromomys maturus Gidley, new genus and species. Genotype. Por- 



tion of a right lower jaw, outer-side view; 3a, tooth-crown view. 



No. 9473 U. S. Nat. Mus. Coll 3 



Plate 2. 



(All figures about 4 times natural size.) 



1. PronothodecUs matthewi Gidley. New genus and species. Paratype, 



Portion of a left lower jaw, outer-side view. No. 9531, U. S. Nat. 

 Mus. Coll 12 



2. Paromomys maiurMS Gidley. Paratype. Portion of a right lower jaw. 



outer-side view; 2a tooth-crown view. No. 9475, U. S. Nat. Mus. 



Coll 3 



3. Paromomys maturus Gidley. Paratype. Portion of a left lower jaw, 



outer-side view. No. 9337 U. S. Nat. Mus. Coll 3 



Plate 3 

 (All figures about 4 times natural size.) 



1. Nothodectes cf. gidley i Matthew. A left upper molar No. 10765 U. S. 



Nat. Mus. Coll. From type locality of Tiffany beds, near Ignacio, 

 Colorado 13 



2. Pronothodectes matthewi Gidley, new genus and species. Genotype. 



Portion of a right maxillary carrying 3 cheek teeth, p* to m.^ No. 



9547 U. S. Nat. Mus. Coll ^ r.. 12 



3. Nothodectes cf. gidleyi Matthew. A right upper premolar, p.'* No. 



10659 U. S. Nat. Mus. Coll. From type locality of Tiffany beds, 

 near Ignacio, Colorado. 



4. cf . Tetonius rex Gidley. New species. Type A left lower molar. No. 



9828 U. S. Nat. Mus. Coll. From Fort Union beds, " No. 3," about 

 4,000 feet higher than the Gidley quarry horizon 11 



5. Palaechthon alticuspis Gidley. Paratype. Portion of a right max- 



illary carrying the three molars, m' to m.* No. 9550, U. S. Nat. 

 Mus. Coll 6 



6. Palaechton alticuspis Gidley. Paratype. Fragment of a right max- 



illary carrying 2 molars, m ' and m.^ No. 9551, U. S. Nat. Mus. Coll. 6 



7. Paronomys depressidens Gidley. new species. Type. Portion of a 



right maxillary carrying 4 cheek teeth, p.'* to m.^ No. 9546 U. S. 



Nat. Mus. Coll 4 



8. cf. Pronothodectes, species. A left upper incisor. No. 10090 U. S. 



Nat. Mus. Coll 14 



9. cf. Pronothodectes, species. A right upper incisor. No. 10010 U. S. 



Nat. Mus. Coll 15 



10. cf. Palaechthon viinor Gidley. A right upper incisor, No. 9928 U. S. 



Nat. Mus. Coll 14,15 



