350 THE GEOLOGICAL MAP OF THE WORLD. 
Emmons, Marsh, Cope and Gilbert in California, Nevada, Utah 
Wyoming, Colorado and Sonora. 
I have preserved the same classification of rocks and the same 
colors, except for the pliocene formation, which I have taken out 
of the tertiary formation to place it with the quaternary and 
modern formations, with which it has more affinities. 
TABLE OF COLORS AND EXPLANATION. 
Pale Yellow. Í Quaternary. } Modern Rocks. 
Pliocene 
Yellow. Í —— { Tertiary Rocks. 
Green, Cretaceous. 
Pale blue, Jurassic. { Secondary Rocks. 
Triassic. New Red Sandstone Rocks. 
Brown Sienna. Dyassic 
Sepia. Sead sereng eon E { Carboniferous Rocks. 
Old Red Sandstone. 
Prussian blue. $ sone ? Palæozoic Rocks or Grauwacke. 
Pink — Crystalline Rocks. 
Vermilion — Volcanic Rocks. 
The classification of stratified rocks is merely provisional, and it 
is really accurate but only for the northern temperate zone, and even 
in that zone itis limited to the basins of the Atlantic Ocean and 
of the Mediterranean Sea. However, as we go from these limits, 
and as we arrive in India or on the Missouri and in California, 
then we encounter difficulties, that have been noticed and treated 
of quite plainly by most observers, which are obstacles which can 
not be passed over in silence nor yet avoided. For a stronger 
reason when we leave the north temperate zone, we find some 
anomalies and difficulties which, far from tending to be cleared up 
with time, on the contrary prove more and more the insufficiency 
of our classifications and the slight value of so-called palæonto- 
logical laws. Let us cite some summary examples :— 
In the Punjab, on the southern’ side of the Salt Range, near 
Jabi, Dr. William Waagen has just found some “Goniatites, 
Ceratites and Ammonites all together in a limestone bed of about 
one foot and a half in thickness, associated with unmistakable 
Producti, Athyris, ete.” (See: On the Occurrence of Ammonites 
associated with Ceratites and Goniatites in the Carbone 
deposits of the Salt Range, “Mem. Geol. Surv. of India,” vol. 
ix, art. 4. That is to say that there occur in the same beds, fos 
