
A NATURALIST IN BRAZIL. 3 
stand it on edge with the covers sloping like the caves of a 
house. This book I place before me in such a way that the 
line of the back will point towards the north-east. This will 
represent the Alleghany Mountains. Now I take a thinner 
book and lean its back against the south-eastern side of the 
dictionary so that it will slope off to the south-eastward, but 
very much more gently than the covers of the dictionary. 
This second book will represent much newer strata, which 
recline against those of the Alleghanies. Among those in 
New Jersey are thick beds of a coarse red sandstone, the 
material out of which brown-stone houses are so commonly 
made in New York City and elsewhere. Geologists call 
this Triassic or New-Red Sandstone. These beds have been 
tilted up since they were formed. Now let us take an- 
other book, and lay its edge just on that of the one last 
laid down, so that it will lie almost horizontally and much 
lower than the rest. This will represent newer strata, 
marls, and sands, etc., of Cretaceous age, which lie still 
undisturbed in the same position in which they were laid 
down. Take another book, and lay it so that its edge will 
overlap that last laid down, and this will represent beds 
of sands, ete., which were deposited after the Cretaceous, 
and which geologists call Tertiary strata. These are also 
undisturbed, and in the same position as that in which they 
were deposited. As we go southward, the Triassic rocks 
disappear from view, and the Tertiary beds lap over the 
Cretaceous, so as to bury them completely. All this will 
appear more plain from the following figure, which is an 
Fig. 2. 

ideal section across the strata of New Jersey, from the moun- 
tains to the sea. æ represents the upturned beds of gneiss, 
etc., of the mountains, against which lie inclined the Triassie, 
or New-Red Sandstone strata, b. Those marked c are Cre- 
