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[Assembly 
slate joins the sandstone, a vein of sulphuret of lead has been dis- 
covered, which is now in possession of a few German miners. Its 
size we could not ascertain, as the workmen were unwilling to ad- 
mit any visitors into the excavation, and were also indisposed to 
give any information upon the subject. 
With regard to the useful purposes to which this rock may be 
applied, we consider it to be well adapted to the construction of 
dwellings in which expensive or ornamental materials are not re- 
quired, and where it occurs in thin layers, for flagging or door 
stones. Near its eastern limit on the Mohawk, it becomes some- 
what argillaceous, and is extensively used for making hydraulic 
cement, which is said to be equal in quality to any in the western 
counties. Masses of this rock which have been exposed for a long 
time to atmospheric agents, are noticed to have lost their calcare- 
ous parts, so that the surface is rough, and upon inspection,, is seen 
to be composed entirely of siliceous particles. 
2. Bastard Limestone. 
The next description of rock succeeding the calcareous sand- 
stone, is an irregular mixture of the latter with grey limestone, 
known as the " sparry limerock" of Eaton, and which we shall 
next describe. The bastard limestone, by which name the quar- 
rymen distinguish it, is of a mottled appearance, occurring in lay- 
ers from six inches to two feet thick, and when it has been long 
exposed to the seasons, the surface exibits irregular projecting 
ridges of siliceous matter, which are disposed in a confused man- 
ner, frequently across each other, and resemble fucoids, or other 
fossil remains. This appearance is noticed particularly on the 
edges of the layers, and is a good evidence of durability in the 
more siliceous varieties of the rock. Although used for buildings, 
it does not work so readily as the grey limestone which overlies 
it, but it is extensively employed tor flagging stones. The lime 
which it furnishes upon being burned, is sandy, and therefore it is 
not much used for this purpose. We noticed quarries of this rock 
at Amsterdam, also near the mouth of Schoharie creek, at the ca- 
nal, and at Canajoharie, in all of which places it occurs in thick 
layers, and convenient for the purpose of quarrying. 
3. Gray Sparry Limestone of the Mohawk Valley. 
The next overlying rock in the series, and which we consider de- 
cidedly the best for architectural purposes, is of a gray or slightly 
