CRETACEOUS FORMATION. 81 



Otherwise tested for this report, and, the results of 

 these tests are to be found below, numbers 170 and 

 171. 



Dr. Eies has testfed also the Carboniferous shales 

 from near Pearce's Mill, in Marion county, and finds 

 them admirably suited for the manufacture of pressed 

 brick and with a mixture of a more plastic clay suit- 

 able for the manufacture of terra-cotta (No. 3.) 

 Up to the present time none of the clays from the 

 Coal Measures have been found suitable for use in 

 the manufacture of high grades of fire brick, but this 

 may be diie to the circumstance that very -few of these 

 clays have beeen examined. Of shales suitable for 

 making vitrified brick, there is the greatest abund- 

 ance. 



CEETACEOUS FORMATION. 



In many respects the mosit important formation of 

 Alabama in respect of its clays, is the lowermost 

 division of the Cretaceous, which we have called the 

 Tuscaloosa. The strata composing this formation 

 are prevalently yellowish and grayish sands, but 

 subordinated to ithese are pink and light purple 

 sands, thinly laminated!, dark gray clays holding 

 many well preserved leaf impressions, and great 

 lenses of massive clays varying in quality from al- 

 most pure white burning clays to dark purple and 

 mottled clays high in iron. 



This formation occupies a belt of country extending 

 from the northwestern corner of the State, around 

 the edges of the Paleozoic formations to the Georgia 

 state line at Columbus. Its greatest width is at the 

 north-western boundary of the State, where it covers 



