THE GLENEYRIE FORMATION 587 
as one goes up in the series, until after 50 feet have been passed a 
gradual transition brings in thinly bedded limestones of Ordovician 
age, known as the Manitou formation. The line of demarkation 
between the Cambrian and the Ordovician in Manitou or Williams 
Canyon may be drawn at the “Narrows” just below the 18-inch 
band of hard, red, porous limestone which contains Dalmanella 
testudinaria. ‘The beds up to this point are lithologically similar to 
the sandstones and limestones at the base of the section to the north 
along Deadman’s Creek described by W. T. Lee,’ and the correla- 
tion is justified by a comparison of the brachiopod faunas of the two 
regions. Near Canyon City, Colo., where cherty layers of the Mani- 
tou limestone rest directly on the granite, the Cambrian is wanting. 
Above the Cambrian in the Manitou or Williams Canyon section 
266 feet of limestones (including the Ordovician or Manitou lime- 
stones) were measured. A marked unconformity appears at the top 
of the series. The limestones at the base of the Ordovician are 
thinly bedded. Higher up the single layers are each one or more 
feet in thickness. Many of them carry chert inclusions. The pre- 
vailing colors are gray, bluish gray, and buff. A few layers near the 
top show deep red. The limestones are rarely free from magnesia, 
but a heavy band near the top is nearly pure lime carbonate. 
The Silurian and Devonian are not known in the section, nor 
anywhere along the Front Range in Colorado. The Harding sand- 
stone and the Fremont limestone of Ordovician age, so well repre- 
sented near Canyon City, are not found in the Manitou region. To 
the north along Glen Eyrie Creek, three miles from Manitou, the 
limestone series is 311 feet thick.2 Here Carboniferous fossils have 
been obtained from the upper beds by Dr. A. W. Grabau. _ It seems 
probable that at this point the equivalent of the Millsap, as suggested 
by Dr. G. H. Girty, is present, although the rock is not lithologi- 
cally similar to the Millsap of the type locality in Garden Park, 
described by Dr. Whitman Cross. In the Manitou Canyon section 
there is no sign of an unconformity to mark Silurian and Devonian 
time until the top is reached. Fossils of Ordovician age occur at 
t American Geologist, Vol. XXIX (1902), p. 96. 
2See reference to Peale’s section in Professional Paper 16, U. S. Geological 
Survey, p. 153. 
