Geology of Jefferson County, Texas. — Kennedy. 269 
cattle ranges, over which the fast diminishing bands of Texas 
long-horned cattle roam at will. A small portion of the north- 
eastern section of the county is timbered with long-leaf pine 
(Pinus palnstris), cypress along the river, and magnolia. The 
rest of the count}' may be considered prairie and more or less 
marshy. 
The climate is mild, almost sub-tropical, and the fig, orange, 
lemon and banana flourish wherever planted. Corn, cotton 
and sugar cane also succeed well. 
Along the Neches at different places, notably at Grigsby's 
bluff, and at various points along Taylor's and Salt bayous, 
mounds of shells occur. These mounds are made up chiefly 
of the Gnathodon cuneatus and lie at considerable distances 
from the sea, the nearest being at least six miles in a direct 
line from the lake. The mound at Grigsby's bluff, by far the 
most extensive of these shell heaps, is about 150 yards long, 
from 15 to 20 yards wide and from 10 to 15 feet high. This 
mound is almost wholly made up of the shells of the Gnatho- 
don cuneatus, with a few fragments of the common oyster and 
Can} in in magnum, all of which are living in the gulf to-day. 
Mr. Rachford, a local naturalist, tells me that several of these 
shell mounds contain remains of human workmanship in the 
shape of broken pottery, arrow points, etc., and that large 
mounds of a similar character occur on the Sabine river near 
the town of Orange, in Orange county. At the time of my 
visits none of these articles were found. 
The geology of the county is in many respects terra incog 
nitn. Nothing but the merest generalization, and that not 
always correct, has ever been given. The region belongs to 
the coastal clay regions of the Texas Geological Survey, and 
Mr. McGee in his "Lafayette Formation" classes it with his 
Columbia formation and considers this essentially an exten- 
sion of the Port Hudson clays of Louisiana. This area he 
describes as follows : 
"In central and southwestern Louisiana the Columbia for- 
mation is a vast sheet of laminated clays, commonly several 
hundred feet in thickness, which toward Atchafalaya bayou 
are frequently blue or bluish gray and charged with carbon- 
ate of lime, of ten segregated in nodular form, while farther 
westward they become brownish <>r reddish in color, non-cal- 
