THE DINOSAURS 93 
disported themselves along the reedy margins 
of lakes and rivers. 
They had their day, a day of many thou- 
sand years, and then passed away, giving 
place to the superior race of mammals which 
was just springing into being when the huge 
Dinosaurs were in the heyday of their exist- 
ence. 
And it does seem as if in the dim and distant 
past, as in the present, brains were a potent 
factor in the struggle for supremacy; for, 
though these reptiles were giants in size, domi- 
nating the earth through mere brute force, 
they were dwarfs in intellect. 
The smallest human brain that is thought to 
be compatible with life itself weighs a little 
over ten ounces, the smallest that can exist 
with reasoning powers is two pounds; this in a 
creature weighing from 120 to 150 pounds. 
What do we find among Dinosaurs? Thes- 
_pesius, or Claosaurus, which may have walked 
where Baltimore now stands, was twenty-five 
feet in length and stood a dozen feet high in 
his bare feet, had a brain smaller than a man’s 
clenched fist, weighing less than one pound. 
