XXVIL | CANADA ELM. 225 
The wood is somewhat darker in colour than the 
Wych, is tough, hard, and of the same porous and 
flexible character, but being more frequently subject to 
star-shake, it is considered to be an inferior variety, and 
is consequently less sought after. It is not generally so 
suitable for boat-board as the Wych Elm, but for any 
ordinary purpose it might be used as a substitute for 
either of the other kinds. In commerce it is known as 
the Dutch or Sand Elm. 
The English Elm trees are remarkable as being among 
the first in leaf in the spring, and the latest in shedding 
them in the autumn. 
THE CANADA ROCK ELM TREE (U/mus Americana) 
is found growing abundantly in the low woods of North 
America, from New England to the Carolinas. It attains 
moderate dimensions, with a clean straight stem, and few 
heavy branches, and yields timber for the market in logs 
of from 20 to 40 feet in length and from 11 to 16 inches 
square. 
The wood is whitish-brown in colour, hard, tough, 
and flexible, with a fine, smooth, close, silky grain; and 
as it has only a small quantity of sap-wood it can be 
worked up closely and economically. It is necessary, 
however, to remove the sap in the conversion of the log, 
as, unlike that of the English Elm, it is of a perishable 
character. 
Rock Elm is often substituted for the English 
common Elm for garboards and planking in ship- 
building, as it is very durable when employed under 
water ; it is also used for ladder steps, gratings, &c., on 
account of its clean whitish appearance; and owing to 
its flexible character it is frequently used in boat-building. 
It cannot, however, be used with advantage in bulk, or 
Q 
