668 GEOLOGY OF OHIO. 
SECTION III. 
THr CLAY WoRKING INDUSTRIES OF OHIO. 
The manufacturing industries included under this head have at- 
tained considerable importance within the last few years, as will be seen 
by the appended statements. 
The first development, of course, began in the manufacture of those 
ruder articles which require comparatively little skill, and which are a 
daily necessity; the work has now extended until it includes a large 
number of the branches of the plastic art, and in many of them a very 
creditable degree of proficiency has been attained. 
The nature of our clay deposits would exclude several branches of 
manufacture from our territory, if we were to be strictly limited to our 
own resources, but several of these are nevertheless carried on in a 
large way on imported material. 
The clay working industries may be divided into several well- 
marked groups, the consideration of each of which, in turn, will form 
the subject-matter of this section. 
The two uses of clay that rise above the rest in importance and 
general application are the manufacture of pottery and of refractory 
material. As both of these uses make the purity and the rarer qualities 
of a clay essential, of course they do not permit so large a development 
as those processes that are satisfied by clay of grosser quality, notably 
those for making building material and pipe. The ornamental clay 
working of course uses less labor and more skill than any of the others. 
POTTERY. 
The manufacture of pottery began in Ohio in very early times, and 
from the rudely-fashioned clay pots of the first settlers has grown the 
industry as it now stands. The different grades of pottery are stone- 
ware, earthen-ware, china-ware, porcelain and ornamental work, all of 
which are made in Ohio, except porcelain, which is made in very small 
amount, if at all, in the United States. 
