292 
The American Geologist. 
November, 1905 
of any Jurassic beds in this part of the continent. Their 
evidence has been even less conclusive than that presented 
by the pioneer geologist just mentioned. It is now known 
that Marcou and his critics were not discussing exactly the 
same thing. 
Independent of whatever may have been concluded in 
the past regarding the presence or absence of Jurassic de- 
posits in the Tucumcari section it is certain that there exists 
at the horizon where the Jurassic system is naturally lo- 
cated in the general geological column, a stratigraphic gap 
and a formation about which there is much to learn before 
their real significance is understood. It may be that after 
all Marcou's surmise was right and that the Jurassic sys- 
tem finds representation in the Cerro Tucumcari, just as it 
now appears that his shrewd guess regarding the Triassic 
eventually proved to be correct. 
In this connection it is of interest to note that in west- 
ern New Mexico, in the'Zuni region, Dutton has regarded 
the great sequence of sandstones which he called the Zuni 
series, and which is upwards of 1,200 feet thick, as very 
likely of Jurassic age. He correlated this series with the 
extensixe deposits of so-called Jurassic age in Arizona, Utah 
and southwestern Colorado. The Zuni series for the pres- 
ent is here still associated with the Triassic system. Its 
stratigraphic relationships, especially with the Dakota 
sandstones, and the position in the Tucumcari region are 
indicated in the section subjoined (Fig. ..). 
The Jurassic Horizon in the Southern Rocky Mountains. 
The horizon represented by the heavy line is worthy of 
much attention. Its stratigraphic horizon is that of the 
Jurassic system of the general geological section. 
