Daily camera., 1901-11-25
soULbER.o N.1At.stA.
Uentia.ed f.en First Pege,

oSA CoVeteO uestiy SNety potVo" VI
Colorado, and q corresponding change
from 4 deep sea to the fresh water
swamps in which were formed the,grea,
coal bed Of Colorado.
"The cap rock Of the great hosback
which rises from Boulder valley, near
the Maiden Rock below the sanitarium,
and which forms the most Of the irregu
lar sky line to the north OF Boulder is
composed Of the quartsitic sandstones
formed while the shores Of the old Colo.
rado islands were fast sinking below the
advancing waves. and which contain
many leaves and other fragments Of
vegetation. washed from the adjoining
lands. The black shales that cover this
formation tell = different story-the
abundant fish scales and numerous sea
shells record the advance of the ocean.
On both sides of Boulder creek may be
seen white ledges of the Niobrara lime
stone. indicating. perhaps. the time when
the sea had gained its greatest depth.
The student who will examine any Con
siderable extent Of this formation will be
rewarded with the discovery of beds OF
fossil molluscs aad perhaps other marine
creatures. The most conspicuous Of the
fossil shells is large thick thelled bi
valve, known as the Inoreramus. 4 dis
tant cousin Of the oyster and the clam
This genus may be distinguished by the
peculiarly of the transverse fibers which
give cross section Of the shell some
what the appearance OF satin spar. The
most prominent species Of this genus in
this formation, often As large as small
pie plate, is marked with . series Of
coarse concentric ridges and grooves.
Another species is a fat shaped Inocer
anus about the sig. and shape Of an
oyster. The larger shells are often Gov.
cred with number OF small oyster shells
about the size OF dime-the Ostrea Con,
gesta. In q strata not tar from this
limestone may be found considerable
quantities OF sharks teeth Of several diff.
ferent species and genera. l have also
obtained from these beds the rare fossil
Radiolites Austinensis and some Mosa
saur teeth.
.The beds above mentioned, which
were Of the Dakota and the Colorado
epochs, do not exceed more than few
hundred feet in thickness, and in the
territory vest Of the Chau.auqua grounds
and the university are reduced to the
thickness Of very tew feet. The whole
valley between Marshall and Valmont
and Boulder is underlaid with a marine
formation some thousands OF feet in
thickness, known ~ the Montana forma
| ton. This formation contains the oil
bearing beds Of the western states, the
oil itself being probably derived from
the decomposition OF the masses of sea
weed which are supposed to have gath
cred in considerable Quantities in the
bay which then existed to the north Of
Boulder, between the foothills and the
projecting headland-the en- echelon
fold to the north of ST. Vrain's creek
The beds are composed Of dull colored
clay and shales broken at times by strata
OF sandsto and limestone. Exposure
of these beds may be seen in several
places along the banks Of Boulder creek
10 the brickyard jus, north Of Boulder.
on the Colorado & Southern railroad
near the university. and on the cas-,
slope of Sherwood heights. Nearly all
the hills and buttes in the vicinity Of
Boulder are composed of cores Of these
Montana beds, covered by thick
veneer of drift from the foothills. Among
these may be mentioned Haystzck
mountain, the hills Immediately north oi
the city, variously known as Lovers,
Zephyr, and Poplar bills. the hills in and
around the Chau,auqua, Sherwood
heights. Beacon hill and the ground on
which the Chautauqua is located. In
former years, considerable quantities Of
fossil shells were gathered in the ravines
near Boulder. bu, in most cases desirable
specimens can now only be obtained by
extensiv. digging"