lierietr of Recent (jreohxjiedl LIteroture. 121 
ly described the Livingstone formation as belonging to the same series. 
The present paper by Hills is mainly a rectification of the nomencla- 
ture. He would now arrange the Huerfano deposits as follows: 
Huerfano Series \ Huerfano beds=Bridger Group. 
(Eocene) ) ^'"uchara beds / (Lower 
' f Poison Canyon beds \ Eocene) 
He considers the Couchara and Poison Canyon beds as the equivalent of 
all the Rocky Mountain Eocene older than the Bridger, including the 
Green River and Wasatch and probably a still older series whose depo- 
sition immediately followed the post-Laramie disturbances. In the lat- 
ter category are placed the Arapahoe and Denver beds, similar beds 
near Canyon City, the Ruby beds, and certain beds in the South park 
and on the Yampa. 
In the paper by Cross the post-Laramie of Middle park is discussed in 
detail. These beds had been previously studied by Hayden, Marvin, 
and White, all of whom agreed in placing them in the "Lignite " or 
Laramie. The determination of their position rests in the main upon 
Marvin's notes and seems to have been based upon the general strat- 
igraphic position, a supposed lithological resemblance and the testi- 
mony of certain jjlant remains, as well, probably, as the absence of any 
strong evidence allying them with any other beds. In an examination 
of the outcrops Cross finds that all the lithological characters which so 
distinctly mark the Denver beds are equally well shown in the Middle 
Park beds. The " doleritic breccia " described by Marvin as underly- 
ing them is shown by Cross to grade up by transition beds into the sup- 
posed "Lignitic." It is made up of a large series of andesitic rocks 
such as characterize the Denver beds at the type locality. Certain of 
the strata contain the same reddish heulandite cement which is also 
characteristic. The whole lithological character of the beds in fact is 
strikingly like the Denver beds and unlike the Laramie proper. Marvin 
noted an unconformity separating the Ijeds in question from the under- 
lying Cretaceous but was disposed to consider it as only of local im- 
portance. Cross shows the greater extent of the unconformity and cor- 
relates it with that which elsewhere succeeds the Laramie proper. The 
evidence fi-om the plant remains cannot at the present time be fully dis- 
cussed since the much needed revision of the Laramie fauna, undertak- 
en by Mr. Knowlton, is not yet finished. Of the twenty-eight species 
found in the old and new collections from Middle park four V)eing doubt- 
ful and three unknown elsewhere, at least twelve occur in the Denver 
beds as developed at Golden. The paleontological evidence would seem 
then to bear out that derived from lithological resemblance and uncon 
formity in placing the Middle Park beds in the series which is at pres 
ent known by the inadequate term post-Laramie. 
In the course of a resume of the geology of Denver and vicinity Can- 
non reviews the history of the discovery of vertebrate remains in the 
Denver V)eds. The interesting discussions which grew out of these dis- 
coveries and were terminated by the description by Marsh, from mate- 
rial collected by Hatcher in Wyoming, of that interesting order of horned 
Dinosauria known as Ceratopsia, are also brought to mind. 
H. K. B. 
