290 PALAEONTOLOGY 



measured, e. g., 1 2£ inches, the middle toe from the same base- 

 line measured 16 inches, the outer toe 12 inches. Some of 

 the impressions of this huge tridactylous footstep were so well 

 preserved as to demonstrate the papillose and striated character 

 of the integument covering the cushions on the under side of 

 the foot. Such a structure is very similar to that in the 

 ostrich. The average extent of stride, as shown by the distance 

 between the impressions, was between three and four feet ; 

 the same limb was therefore carried out each step from six to 

 seven feet forward in the ordinary rate of progression. 



These footprints, although the largest that have been ob- 

 served on the Connecticut sandstones, are the most numerous. 

 The gigantic Brontozoum, as Principal Hitchcock proposes to 

 term the species, "must have been," he writes, " the giant rulers 

 of the valley. Their gregarious character appears from the 

 fact, that at some localities we find parallel rows of tracks a 

 few feet distance from one another." 



The strata of red sandstone, with the above-described im- 

 pressions, occupy an area more than 150 miles in length, and 

 from 5 to 10 miles in breadth. " Having examined this series 

 of rocks in many places, I feel satisfied that they were formed 

 in shallow water, and for the most part near the shore ; and 

 that some of the beds were from time to time raised above the 

 level of the water and laid dry, while a newer series, composed 

 of similar sediment, was forming." "The tracks have been 

 found in more than twenty places, scattered through an extent 

 of nearly 80 miles from 1ST. to S., and they are repeated through 

 a succession of beds attaining at some points a thickness of 

 more than 1000 feet, which may have been thousands of years 

 in forming."* 



One of the evidences of birds from the Cambridge green- 

 sand, transmitted to the writer by their discoverer, Mr. Barret, 

 is the lower half of the trifid metatarsal, showing the outer toe- 



* Lyell, Manual of Elementary CJeology, 8vo, 1855, p. 343. 



