i6 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. -/-] 



In addition to the specimens mentioned above, the collection con- 

 tains numerous short series of tracks, none of which is worthy of 

 special mention. In plate 9 is shown a trackway of Laoporns nobeli 

 diagonally crossing that of Baropesia cakini. 



Comparative Measurements 



Type 

 No. 2, 144 

 YaleMus. ICJ. S. N. M 



K^n^'s^r, No. 11,148 



^o-M2A lu. S. N. M. 



No. II, 122 

 U. S. N. M. 



Manus 



Length 



Width 



Length of digit I . . 

 Length of digit II . 

 Length of digit III 

 Length of digit IV . 



Pes 



Length 



Width 



Length of digit I . . 

 Length of digit II . 

 Length of digit III 

 Length of digit IV- 

 Length of digit V . 



Length of stride 



Width of trackway. . 



m m . 

 20.0 

 21.0 



22.0 

 31.0 



mm. 

 20.2 

 22.5 



6.0 

 12.5 

 10. 



6.5 



24.0 



28. 5 



119 

 100 



vim. 

 19.0 

 23.0 



3-0 

 9.0 



9.0 



24.0 

 28.0 



6.0 



lO.O 



10.5 

 105.0 



104.0 



mm. 

 21.0 

 25.0 



8.5 

 13.0 



II. 5 



26.0 



32.5 



50 



12.0 



12.5 

 ISO 



LAOPORUS COLORADOENSIS (Henderson) 



Plate 7, figs. I, 2 



Limnopus {?) coloradoensis Henderson, Junius, Journ. Geol., Vol. 32, No. 3, 

 1924, p. 228, figs. I, 2, 3. 



Through the courtesy of Prof. Junius Henderson of the Univer- 

 sity of Colorado, the type and figured specimens of Limnopus ? 

 coloradoensis (Nos. 13238, 14140 and 14141, Univ. of Colo.) from 

 the Lyons sandstone {Permian), Lyons, Colorado, were loaned me 

 for study and comparison with the footprints from the Grand Canyon. 



In the original description this species w^as questionably referred 

 to the genus Limnopus founded by Marsh ^ upon tracks from the 

 Coal Measures of Kansas. (See fig. 8.) The presence of five dis- 

 tinct digits in the pes and four in the manus, with traces of claws, 



^ Marsh. O. C , .\mer. Journ. Sci , Vol. 48, 1894, p. 82. 



