OF NORTH AMERICA. 
95 
the same formation e.xtcnds along the shores of the Bay to and beyond San Jose. Not only the extent 
and position, but the lithological characters of these rocks are discussed in a published report, ”) which 
was in the hands of the author of the map previous to its publication. {This assertion is erroneous, / 
did not receive Williamson's «Report» until June 1856. — J. Marcou.). The representation of the granitic rocks 
is not confined to the end of the peninsula, but is continued southward to the western shores of the 
Tulare lakes where the formations are chiefly miocene tertiary, the eruptive rocks scarcely appearing. 
The promontory called Point Pinos, which forms the headland of the Bay of Monterey, is repre- 
sented as tertiary, while a porphyritic granite constitutes the whole point and forms the coast-line south 
to the Bay of San Carlos, and is probably continuous southward to San Luis Obispo; forming a hi<di 
and unbroken line of coast, all of which is colored tertiary on the map. Casting the eye further south, 
we find the color denoting the eruptive and metamorphic rocks again usurping the place which should 
be colored tertiary, at Point Conception, which consits of beds of conglomerate and sandstone. 
The broad alluvial ti-act at the head of the Gulf of California — the Colorado desert — is made 
to extend nearly due north and parallel with the Colorado to the Soda Lake. The published description 
of this valley gives its direction as northwest and southeast, extending to the foot of San Bernardino 
Mountain. 
The extensive coal-fields of Puget Sound and the Coast of Oregon are represented as Upper Car- 
boniferous or of the true coal-period. All the evidence which can be procured concerning the age of 
these deposits shows them to be Tertiary. The ressemblance of the sandstone found with the coal to 
that of San Francisco, and the presence of Pectens in it has been noticed in published reports. Obser- 
vations by Prof. J. S. Newberry reported since the publication of the map show that these coal-deposits 
are undoubtedly Tertiary.'’) 
In the region of the Wind River mountains, a range called the Black Hills, extending northeast of 
the Platte, has found a place in most of our maps. We find the geological structure of this ran^e 
indicated on the map, as granitic and carboniferous, while on another map published in Gotha, it is 
represented as composed of cupriferous trap. A recent exploration of that region by Lieut. G. K. Warren, 
U. S. A. , shows that this range is purely imaginary and should not appear on the maps north of the 
Platte. 
According to the map, the region of the South Pass is occupied by a belt of cujiriforous trap, 
extending over at least two degrees of longitude , and in a northeast and southwest direction , with the 
same trend as Keweenaw point and Isle Royale, Lake Superior. There is no record of any such out- 
crops as this in any of the reports of explorers who have visited that region. Fremont, Stansbury and 
others, found horizontal sedimentary formations resting on granitic rocks. °) 
The Wind River range, which according to Col. F'remont and his collection, is granitic and meta- 
morphic, trending north-westerly, is not represented on the map. Fremont’s peak, however, the high- 
est peak of the range, and described by F’remont as composed of granite, gneiss, syenite, and syenitic' 
gneiss, is represented as a volcano. The Raton Mountains are also colored as volcanic ; in .Abort s 
Report^ they are described as sedimentary, and coal-plants were obtained there and figured in the report ''). 
These, however, are but inconsiderable errors when compared with the representation of the geolo- 
gical age of the strata forming the broad table lands on each side of the great central chain of moun- 
tains. These arc represented as Jurassic above and Triassic below'. The Jurassic forms a conspicuous 
feature on the map and includes the Llano Estacado, and all the table-lands from the Missouri to the 
Rio Grande. It is surrounded by a much broader coloring representing the trias. A'et there is no 
”) Preliminary Geological Report on the Pacific Railroad Route, surveyed by Lieut. R. S. Williamson in Cali- 
fornia, House Doc., 129, Washington, D. C., Jan. 1855. 
Proceedings of the American Association for the Advancement of Science. Albany, 1856. 
') See the descriptions of the collections by Prof. James Hall , and report of Col. J. C. Fremont, p. 295. 
') Report of an Examination of New Mexico, by Lieut. J. W. Abert, U. S. Top. Engineers, 1848. 
