Sedgwick. . 49 
This source of lasting sorrow to both, if it cannot be forgotten, 
ought to be only, remembered with the tenderness of regret. 
amiliar as we now are with the rich fauna of the Cambrian 
and Silurian rocks, and their equivalents in Bohemia and 
mundi,” almost to complete the physical history of the earth. 
Starting with a general view of the lake mountains of the north 
of England, and the great dislocations by which they have been 
separated from the neighboring chains (Geol. Proc., Jan, 1831), 
Sedgwick won his difficult way through North Wales to a gen- 
eral synopsis of the series of stratified rocks below the Old Red 
sandstone, and attempted to determine the natural groups and. 
formations (Geol. Proc.. May, 1888). Three systems were: 
named in order—Lower Cambrian, Upper Cambrian, Silurian—. 
the working out of which, stream by stream, and hill by hill,, 
worthily tasked the energies of Ramsay and his friends of the: 
National Survey for many useful years, after increasing ill- 
health had much reduced the field-work of the Professor. 
€ to his assistants more than the praise and the delicate: 
attention which their services deserved. 
| € ample volume entitled “British Paleozoic Rocks and 
Fossils, 1851-5,” by Sedgwick and M’Coy, must be consulted 
for a complete view of the classification finally adopted by 
Am. Jour. op tems a Series, Von. VI, No. 31.—JuLr, 1878. 
