1889.] Geology and Palaeontology. 713 
leith-adamsii, the remains of which are found in Germany, and are well 
represented in the museum of the University of Bonn. 
The memoir is a most important contribution to a difficult part of the 
subject, and will be welcomed by all paleontologists. — E. D. Cope. 
The Cretaceous Formation of S. W. Maryland.— For many 
years past the Tertiary formation of this section was an enigma 
which, under the light of the past, could not be satisfactorily resolved 
in accordance with the generally accepted theory that where the 
Tertiary formation was located, there was no other system to be looked 
for. 
That idea has been a stumbling block that but few have been able 
to get over in a satisfactory manner. 
The great cliff at Fort Washington, Prince George's count}-, has been 
to the author for the last twenty years a sealed book, an enigma not to 
be translated by any one, because, surrounded on all sides by Eocene 
deposits, it gave no sign of Eocene fossils, notwithstanding it stood up 
to an elevation of from 60 to 65 feet. 
But recent ideas suggested by the work and labors of Prof Wm. B. 
Clark, of Baltimore, have thrown off the confusion and made that 
locality readable. Visiting that formation recently we found evidences 
sufficient to put it down as Cretaceous. At this cliff we found Eocene 
shells scattered around — not in situ, but amongst the fallen debris — 
sufficient to prove it was once covered with the Eocene deposit, which 
is well developed higher up both Swan Creek on the north and Pis- 
cataway Creek on the south. We found both fossils, shells, and casts, 
plants and lignite in the cliff; one plant in my collection could be 
determined by an expert, from the leaves or parts of leaves which were 
collected. 
A result of the examination of the cliff was the fact that we found it 
to rest upon a bed of variegated Jurassic clay, from one to two feet 
above high water mark, in which there is lignite. Further up Piscat- 
awa\- creek we found years ago large coprolites, pieces of bone, sharks' 
teeth, and palates of sharks, and amber, now in the possession of Mr. 
Philip Uhler, of Baltimore. We did not then know what these meant, 
but ])y the light of to-day we have to admit the formation to be, con- 
trary to the generally received opinion. Cretaceous. The village of 
Piscataway is upon that formation. The old men of that place in- 
formed us that all the wells dug in that village since they could 
recollect, went down upon and into black micaceous sand and clay, 
and that they got water at from twelve to twent)' feet. Traxeling out 
from thence we found the Cretaceous clavs co\ered with Eocene beds in 
