SCIENTIFIC SUMMARY. 
91 
Relation of Orders of Reptiles to Strata . — Professor Cope, who has already 
so much distinguished himself upon American palaeontology, gives in a 
recently-published memoir the following tabular arrangement of this class, as 
regards its rocks, which contains these remarks : Present Time — Rhynchoce- 
phalia; Crocodilia; Testudinata; Lacertilia; Ophidia. Pliocene — Croco- 
dilia ; Testudinata ; Lacertilia ; Ophidia. Miocene — Crocodilia ; Testu- 
dinata ; Lacertilia ; Ophidia. Eocene. — Crocodilia ; Testudinata ; Lacertilia ; 
Ophidia. Cretaceous. — Ornithosauria ; Dinosauria ; Crocodilia ; Sauro- 
pterygia ; Testudinata; Lacertilia; Pythonomorpha. 
The Geology of Salt-Lake City. — Mr. W. P. Rlake has written a letter 
to Professor Silliman in which he describes briefly, but pretty generally, the 
geology of the Salt-Lake City. He says that he left New Haven hurriedly 
to reach the Emma Mine and examine it. It is a remarkable mine. Within 
a little more than a year it has yielded ore worth over $2,000,000, and 
this without any special outlay. It is a great mass of soft earthy-looking 
ore, the result of the decomposition of argentiferous galena. It is dug out 
with shovels and picks, sacked, and sent to Liverpool, where it sells for 
about $175 per ton. The mass is between strata of limestone, the middle 
members of a series of strata over a mile thick. The lower members are 
slate and quartzite, and rest upon the immense masses of syenitic granite 
which form the picturesque Alpine-like peaks of the Wahsatch. These 
strata are all much uplifted and contorted, some of the harder beds surging 
up into peaks at least 11,000 feet above tide. The mine is at an elevation 
of 8,500 to 9,000 feet. At the head of the canon upon the side of which it 
is situated, there is a fine exposure of syenitic granite for about a mile, with 
rounded polished backs — roches moutonnees — probably 9,000 feet above tide. 
These rocks give conclusive evidence of the former existence there of a 
large glacier. Much of the polish upon the surface has been removed by 
the action of the weather. The patches that remain are dark brown in 
colour, while the syenite is light grey, and they show the same peculiar 
scale-like crusts seen on the partly weathered glaciated surfaces above the 
Yosemite. 
Geology of the Rocky Mountain. — a Harper’s Weekly,” an American 
literary journal, gives the following account, which may be of interest to 
our readers. . The geological expedition to the Rocky Mountain region under 
the charge of Dr. Hayden, after completing the survey of the Yellow Stone 
Valley, left Fort Ellis on September 5, passing down Gallatin Valley to the 
Three Forks, and thence by the Jefferson to its very source, exploring 
many of its branches, and pursuing a direction nearly parallel to that which 
the party had traversed in the June previous. The valleys of the Gallatin, 
Madison, and Jefferson Forks of the Missouri, with all the little branches, 
were found occupied by industrious farmers and miners — a contrast quite 
striking to the doctor, who, twelve years ago, in exploring that same region, 
met with not a single white inhabitant. The Rocky Mountain Divide was 
crossed at the head of Horse Plain Creek, from which the party passed over 
into Medicine Lodge Creek, following this down into the Snake River 
Plain. 
Results of the Coal Commission. — This important Commission, which has 
been sitting for some years, has just published the first volume of its Report. 
