THE FOSSIL FOOTMARKS OF THE UNITED STATES. 199 



ture of the outer toe, 0. 1 inch. Heel sloping upwards posteriorly, 

 in a gradual manner, so as to leave an impression on the mud a great- 

 er or less distance. Feet for the most part plantigrade. Distance be- 

 tween the roots of the three forward toes and the hind toe, 0.7 to 

 0.9 inch. Track shown, of the natural size, on Plate 9, figs. 2, 3. 



Localities. — Chicopee Falls, one mile south of Cabotville ; and 

 at Wethersfield. 



Remarks. — The singular manner in which the hind toe on the 

 track of this and the following species, from being on the upper 

 layer at right angles with the heel, changes in passing downwards, 

 so as to correspond almost with that of Ornithopus gallinaceus, has 

 been already noticed in describing the tenth general character. 

 This fact shows us that little dependence can be placed upon this 

 character ; and it approximates two species of tracks, which, at 

 first view, seem very much unlike, namely, Ornithopus gallinaceus 

 and Plectropus minitans. 



Species 2. Plectropus longipes. (PI. VIII. Fig. 4; PI. X. Fig. 1-3.) 



Sauroidichnites minitans, Mass. Geol. Rep., Plate SS, fig. 12. 



Nos. 24-26, 154, 155, 163, 164, 171, in Cabinet. 



Divarication of the lateral toes, 70° to 75° ; of the inner and 

 middle toes, 30° to 37° ; of the middle and outer toes, 40° to 45° ; 

 of the middle and hind toes, 90° to 100°. Length of the middle 

 toe, 2.1 to 3.5 inches; of the inner toe, 1.4 to 2 inches; of the 

 outer toe, 1.7 to 2.5 inches ; of the hind toe, 0.6 to 1 inch ; of the 

 heel, 2.6 to 5.7 inches ; of the foot, 6 to 9 inches ; of the step, 14 

 to 17 inches. Width of the heel, 0.3 inch; of the foot at the 

 roots of the front toes, 0.4 inch. Distance between the tips of 

 the lateral toes, 2.2 to 2.6 inches ; between the inner and middle 

 toes, 1.4 to 1.9 inch; between the outer and middle toes, 1.6 to 



