FOOTPRINTS ON THE SANDS OF TIME 49 
toes that were used (functional toes), and that they had the 
same number of joints in their toes as birds, has naturally led 
scientific men to the opinion that probably all the tracks above 
described were made, not by birds, but by Dinosaurs. It may 
be pointed out in defence of this opinion, that, although the 
two classes of Birds and Eeptiles are now widely separated, yet 
in certain former geological periods there was no such gulf as 
now divides them. At the time when the Connecticut Sandstone 
tracks were made on the shores of a narrow inland sea, there 
must have been in existence animals which, if we saw them 
now, might sorely puzzle us to decide whether to call them 
reptilian birds, or bird-like reptiles. 
During the Jura-Trias period there was in the region of 
the Connecticut Valley a shallow sea, connected by a narrow 
outlet with the ocean. Into this the tides flowed and ebbed, 
leaving extensive flats of mud or sand, ribbed with ripple-marks. 
A passing shower pitted the soft mud, and the sun, coming 
out again from the breaking clouds, dried and cracked it. 
Our Dinosaurs and other creatures sauntered or ran near the 
margin of the shore. The tide came in again, carrying with 
it fine sediments, gently covered the tracks, and preserved them 
for ever. This occurred constantly for many ages, about the 
time when the Triassic period came to a close. 
In the year 1882, reports were published of the discovery of 
large footprints — supposed to be human — in a certain sandstone, 
near Carson, Nevada, U.S., of which a brief account was given in 
our former work.^ These are probably the tracks made by a big 
extinct sloth of the Pleistocene period. The wonderful series of foot- 
prints of reptiles, birds, and mammals discovered by M. Desnoyers, 
in certain Eocene strata near Paris, cannot be described here. 
^ Extinct Monsters, p. 185 (2nd edit.). 
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