PROTOZOA 53 
stratified rocks are estimated to be of a tremendous 
thickness, and you might naturally conclude that 
the older rocks must be very deep beneath the 
earth’s surface. Many of them are hidden away at 
great depths, but thanks to earth movements spoken 
of in the last chapter, the strata in many places have 
been tilted upwards, and even set on edge, so that 
we can walk over and examine outcrops of rocks, 
which, if it were not for ages of earth movements, 
would be overlaid by many thousands of feet of 
other deposits. 
And now for the Fossils. 
I shall tell you first about fossil animals, and after- 
wards call your attention to fossil plants, and I shall 
begin with the lowest members of the Animal King- 
dom—namely, those which belong to the first of the 
eight great subdivisions of the animal world. These 
are called Protozoa (Greek, protos = first, zoon= 
animal). The simplest members of this division are 
very minute, jelly-like masses, without legs, arms, 
eyes, stomach, or any organs, yet they can move, 
swim, feed, and feel; they can also multiply them- 
selves by division of their own substance. As they 
have not any skeletons or hard parts, we have no 
fossil remains of these lowly creatures. There are, 
however, very lowly, jelly-like creatures which clothe 
themselves with a covering of carbonate of lime, 
which they extract from the water in which they 
live. They are very small, and you need a micro- 
Scope to examine them with. Their coverings are 
often like little globes, or several little globes joined 
together, and they are pierced with little pores, or 
holes, through which the tiny animals thrust portions 
