Clay. 'Riis deposit is extensively distributed in the valleys and low- 
grounds of the counties examined. The valleys between the ridges in 
the north part of Ontario and Seneca counties are clay, with sometimes 
a slight admixture of other ingredients. Tlie destruction of northern 
portions of the Onondaga saliferous group has doubtless given rise to a 
large proportion of the clay, which from remaining longer suspended 
in the water was deposited upon all the other materials. Bricks made 
from this substance are usually of a light colour, and from the large 
admixture of calcareous matter are of inferior quality; though to many 
beds of clay this objection does not apply. 
Boulders of granite, gneiss and other ancient rocks are scattered upon 
the surface or imbedded in the soil. Besides these are fragments of 
limestone and some other rocks of the district j as of the Tully lime- 
stone in the valley south of Seneca lake. One of these masses is fifty 
feet square and six feet thick. Numerous others are found of less di- 
mensions, which furnish lime for the country around. These have 
scarcely been worn by attrition, but present the appearance of fragments 
just removed from the parent rock, while their nearest locality is from 
thirty to forty miles. Fragments of the conglomerate above the Che- 
mung group occur in many of the valleys; these bear evidence of 
attrition, and have probably been derived from the tops of the neigh- 
bouring hills. 
Upon the lands of the Messrs. Lawrence, in the valley on either side 
of Cayuga lake, are several large angular masses of rock, differing from 
any seen before in the district either in place or otherwise. Some of 
these have the colour of red sandstone, approaching to that of red 
jasper; others are nearly white, with veins and irregular spots of red; 
the rock is exceedingly hard and tough, presenting an uneven fracture. 
It effervesces slightly with acids. From comparison, it proves to be 
the same with the altered silicious limestone described by Prof. Emmons, 
as resting on the slate at Burlington, and doubtless equivalent to all 
the limestone of the western part of Massachusetts, usually termed 
primitive. A circumstance very remarkable is that none of these frag- 
ments have heretofore been observed, the present being more than 250 
miles from the nearest locality of the rock. 
Lake Marl and Tufa are very abundantly distributed over many parts 
of the counties examined) and are already becoming useful both for 
lime and agricultural purposes. Along the line of the saliferous group, 
these substances are abundant, arising from the decomposition of the 
