370 
[Assembly 
brittle till the moisture has evaporated, when it is one of the toughest 
stones we have. Moisture in a crystalline rock is sufficient to expand 
the particles beyond their powers of cohesion if exposed to frost when 
first quarried. It should be understood, however, that after a stone is 
once dry it does not absorb this moisture again, even if wet or immers- 
ed in water. Before it was a part of its composition, and cannot again 
be acquired unless the particles of the rock be placed in the same con- 
dition as at the time of its formation. 
The Lockport stone is a better material for w^orks on the canal than 
any within the limits of the Fourth District. It would be greatly to the 
advantage of the State and to the durability of the Rochester aqueduct, 
if the Lockport stone were substituted for that now being used; a large 
amount would also be saved in transportation. 
The importance of proper materials for construction is overlooked 
both in private and public works. From data obtained on this subject, 
I have ascertained that the State of New-York has sustained a loss of at 
least $1,000,000 from the use of improper materials for construction on 
the Erie canal since its commencement; and thousands of dollars annu- 
ally would be saved by employing some experienced person to select 
stones and cements for use on the canal. 
Variegated Marble of Lockport, 
At the village of Lockport we find the same strata as at the Cold 
Spring quarries, but here they are more compact in texture, and con- 
tain abundance of fragments of encrinital columns. These columns, 
and a few other fossils in the rock, have a reddish brown colour, giving 
to the surface a beautifully variegated appearance. The rock is suffi- 
ciently compact to be polished, and has been used for some ornamental 
purposes; it is called " Lockport Marble." There is a fine polished 
specimen in the collection presented to the State by Mr. Hathaway of 
Lockport; also several other specimens not polished were presented by 
Messrs. Hawley and White. 
The variegated strata are from five to eight feet thick, and extend 
over an area of many acres. This marble will doubtless become valua- 
ble at some future time, when the demand is more than at present. 
Flagging Stones. 
Flagging stones of the finest quality are obtained from the sandstone 
referred to under " Materials for construction.^^ The principal quarry 
