GEOLOGICAL SKETCH 
OF THE 
ESTUARY AND FRESH WATER DEPOSIT FORMING 
THE RAD LANDS OF JUDITH RIVER, 
WITH SOME REMARKS UPON THE SURROUNDING FORMATIONS. 
By F. V. HAYDEN, M. D. 
(Read before the American Philosophical Society, March Ath, 1859.) 
EXTINCT VERTEBRATA FROM THE JUDITH RIVER, 
AND 
GREAT LIGNITE FORMATIONS OF NEBRASKA. 
By JOSEPH LEIDY, M.D. 
(From the Transactions of the American Philosophical Society.) 
PHILADELPHIA: 
WILLIAM S. YOUNG, PRINTER TO THE SOCIETY, 52 NORTH SIXTH STREET, BELOW ARCH. 
1859 
