410. 
[Assembly 
however, is not so great as, from its extending over so great a surface, 
I had heretofore supposed. 
In Scio it is found on the high grounds near the sources of some 
small streams flowing into the Allegany and Genesee. For the most 
part the rock appears in large detached masses, being divided by the 
joints into rhombic blocks ; one of these measured 44 by 60 feet, and 15 
feet in thickness. Approaching the rock in place the masses are larger 
and closer together, being but slightly moved out of place, and the 
spaces between them diminishing from a distance of five or six feet to 
fissures of a few inches. The sides of the blocks appear water- worn, 
or deeply weathered ; and the upper surfaces slope in the direction of 
the hill, probably from the removal of the rock beneath. The mass 
seems to have contracted on dessication, and the joints, since enlarged 
by the percolation of water from above, form within the rock passages 
of greater or less extent, communicating with each other. The pecu- 
liar features in other localities will hereafter be mentioned. 
This mass is composed of pebbles of crystalhne quartz, white or 
rose colored, from one to two inches in diameter, and generally elon- 
gated or egg-shaped. In the early settlement of the country this rock 
was used for mill stones ; but in much the greater part the pebbles are 
too large and it is too friable for this purpose ; its use is now super- 
seded.* 
Previous to visiting this place I was informed that a bed of coal two 
feet thick had been found beneath this conglomerate ; it was represent- 
ed as having been used in the blacksmiths' forges. On further inquiry 
I could not learn that such a bed was known ; the only person who 
could give any information of its existence had seen small pieces not 
more than one-half inch in diameter. 
This rock is the only one seen between Wellsville on the Genesee 
and Bolivar, a country which is entirely a wilderness. 
In the town of Genesee, about three miles north of the Pa. line, and 
near the centre of that town, the conglomerate, essentially the same as 
at Scio, occurs on the highest hills. 
* The conglomerate is an excellent material for roads ; and if thrown down in mo- 
derately large pieces, would soon, from its friable nature, be broken down, forming a 
fine gravelly surface superior to the McAdam roads. 
