EXPLANATION OF PLATE 26 a . 41 



Fig. 1. Ornithichnites giganteus. Many tracks of this 



species occur at Mount Tom, near Northampton, 



U.S. 

 Fig. 2. O. tuberosus. Portions of three tracks, and a 



single footstep of a fourth appear on the same slab. 



The two longest of them are in opposite directions. 

 Fig. 3. O. tuberosus, on a slab in front of the Court House 



in Northampton, from Mount Tom. 

 Fig. 4. O. ingens, from a quarry called the Horse Race, 



near Gill. The appendage to the heel is not distinct 



in this track. 

 Fig. 5. O. diversus, on a flag-stone near the first church 



door at Northampton, U. S. 

 Fig. 6. O. diversus. We have here three rows of tracks 



and a single footstep, from the Horse Race Quarry. 



These tracks show no marks of any appendage to 



the heel. 

 Fig. 7. O. diversus ; found near South Hadley, U. S. 

 Fig. 8. O/diversus; curvilinear track from the Horse 



Race Quarry. 

 Fig. 9. O. diversus. Two parallel tracks from the Horse 



Race Quarry. 

 Fig. 10. O. diversus; nearly parallel tracks of two birds, 



with an appendage behind each foot ; from the 



quarries at Montague, U. S. 

 Fig. 11. O. minimus; common at the Horse Race 



Quarry ; similar impressions of the feet of small 



birds vary from half an inch to an inch and half 



in length. 

 Figs. 12. 13. 14. O. diversus; from the Horse Race 



Quarry. Tracks of different individuals of different 



species, and different sizes cross one another con- 

 fusedly in these three slabs. 

 Fig. 15. Recent track of probably a Snipe. 



3* 



