Limestone Strauta.— Blake. AT 
tion. What we possess is the general fact that a similar flora 
once existed in two partsof the world very widely separated, and 
until some other facts are discovered which complicate and vitiate 
such a conclusion, it is both safe and useful for the geologist to 
regard the two deposits as belonging to the same geologic age. 
There are certain limitations within which this must be true, and 
when these limitations are recognized the paleontologist may as 
safely draw his conclusions as he could before the law of homo- 
taxis had been formulated. 
Age or FHE LIMESTONE STRATA OF DEEP 
CREEK, UTAH, AND THE OCCURRENCE 
OF GOLD IN THE CRYSTALLINE POR- 
TIONS OF THE FORMATION. 
By WitiraM P. Biake, Shullsburg, Wis. 
The Deep Creek region, so called, lies along the western border 
of Utah territory and nearly southwest of the Great Salt lake. 
It borders upon the state of Nevada, and has lately been brought 
into prominence by reason of the development of deposits of 
argentiferous lead ores and of auriferous copper ores. The pre- 
vailing formations are granite and limestone. The limestone is 
largely developed, and forms ranges of hills and mountains of 
considerable extent, trending generally in a northerly and 
southerly direction, parallel with the ranges of Tintic and of the 
southern end of Salt lake. The principal range, known as the 
Ibapah, forms the eastern side of Deep Creek valley. Ibapah 
mountain, the highest peak of the range, is said to be the 
highest mountain in Utah; higher even than any of the grand 
mountain masses of the Wahsatch, not excepting Mt. Nebo. 
Ibapah is flanked on the north by massive strata of limestone, 
which in some places, notably at Gold Hill, are much uplifted 
and metamorphosed apparently by intrusions of granitic and 
porphyritic dykes, the alteration consisting in loss of color (the 
ordinary grayish-blue color being changed to white), a coarse 
crystallization, and the formation of a variety of silicates, such 
as garnet, tremolite and tourmaline, especially near the planes of 
