4 fg en iy de. 
CONTRIBUTIONS 
i 
TO 
GEOLOGY. 
“ 
BY 
ISAAC LEA, 4 
MEMBER OF THE AMERICAN PHILOSOPHICAL SOCIETY ; 
OF THE ACADEMY OF NATURAL SCIENCES OF PHILADELPHIA ; 
OF THE LYCEUM OF NATURAL HISTORY OF NEW YORK ; 
HONORARY MEMBER OF THE MEDICAL SOCIETY OF ORANGE COUNTY, 
NEW YORK; 
MEMBER OF THE ROYAL PHYSICAL SOCIETY OF EDINBURGH; 
OF THE BRITISH ASSOCIATION OF SCIENCE; 
OF THE NATURAL HISTORICAL SOCIETY OF MONTREAL ; 
CORRESPONDING MEMBER OF THE LINNAAN SOCIETY OF BOURDEAUX, 
ETC. ETC. 
PHILADELPHIA: 
CAREY, LEA AND BLANCHARD. 
1833, 
