140 FLORIDA GEOLOGICAL SURVEY—15TH ANNUAL REPORT 
weekly to New Orleans from Pensacola. He also states that fire-brick 
in particular were in great demand and brought a very good price. The 
same author, writing in 1837 1 , reiterated the same conditions. 
Crary 2 made both mud and dry-press brick on Escambia Bay from 
1856 to 1860 for the construction of Fort Jefferson on Dry Tortugas 
Island. He later established a brick plant at Bluff Springs in the north¬ 
ern part of Escambia County. The same author, 3 in writing of fire-clays, 
says “the best developed beds of fire-clay are found in Escambia County, 
Florida. In fact, the whole county is underlain with one vast indetermin¬ 
able bed of potter’s clay and fire-clay, in strata from six to forty feet deep, 
often cropping out on the surface. This clay is suitable for all kinds of 
pottery, for fire-brick, and for the very best kinds of building brick, 
or blocks for paving, and is cheap, accessible and in every way advan¬ 
tageously situated for profitable manufacturing.” Crary, however, de¬ 
fines fire-clay as “antediluvial or primitive clay”. 4 The term “primitive 
clay” is here applied to bedded deposits of clay which were not of flood¬ 
plain origin. This definition of a fire-clay is not now accepted and the 
clays of Escambia County referred to by Crary are not fire-clays. 
The Citronelle formation underlies much of Escambia County and 
in most places is overlain unconformably by more recent sediments. Both 
the Citronelle formation and the undifferentiated Pleistocene sediments 
above consist essentially of lenticular, cross-bedded and interstratified 
sands and clays. Clays, however, form the greater part of the Citronelle 
section while sands prevail in the Pleistocene deposits. 
An erosional unconformity separates the Citronelle formation from 
the Pleistocene. Other minor unconformities may be observed in 
numerous places. In a sand-clay pit about five miles north of Pensacola 
on the Flomaton road an unconformity occurs between two clays and is 
marked by a half-inch layer of limonite. 
Layers of limonite, in places as much as six inches in thickness, are 
of common occurrence in several of the clay exposures where they mark 
the contact between two clays or between a sand and a clay. These 
limonitic layers probably represent zones of concentration formed from 
descending waters which have leached out the iron from the overlying 
1 Williams, lohn L., Territory of Florida, p. 114, 1837. 
2 Crary, J. W., Sr., Brickmaking and Burning, pp. 14 and 35, 1890. 
3 Same, p. 3. 
4 Same, p. 28. 
