14 W. P. JENNY 
Area east of geosyncline.—East of the geosyncline are found two 
trends of magnetic “highs,” which parallel the axis of the Sabine 
uplift: (1) the Farmerville-Columbia-Harrisonburg trend and (2) the 
Bastrop- Winnsboro trend. : 
On the second trend lie the gas fields of Monroe and Richland. 
The magnetic “high” indicated slightly north of Bastrop is interpreted 
as an uplift in the deep basement rocks, which uplift accounts for the 
Monroe gas field. From magnetometer work we know that half way 
between Rayville and Winnsboro a similar magnetic ‘“‘high”’ and cor- 
responding uplift accounts for the Richland gas field. 
The magnetic “high” as indicated south of Winnsboro therefore 
suggests other possibilities of uplifts along the known trend toward 
the south. 
Central Louisiana.—A magnetic “high” south of Colfax is indi- 
cated. 
The concurrence of the horizontal vectors of Jena, Alexandria, 
and Marksville at a point about 1o miles northeast of Marksville 
suggests a magnetic and possibly structural ‘‘high” of large dimen- 
sions at that point: 
Other magnetic “highs” are suggested between Leesville and De 
Ridder and southeast of Cheneyville. 
At St. Francisville and New Roads there is a striking example of 
two stations which may reasonably be assumed to lie on the same 
“structure.’’ The magnetic lines of force come out of the ground ata 
low angle at St. Francisville, assume a horizontal direction between 
the two stations, and penetrate into the ground at a low angle at 
New Roads, directed toward a magnetically positive ‘‘structure” on 
the south. 
The distances are too great to say that this “structure” is the 
eastern extension of a west-east ridge or anticline as indicated be- 
tween Ville Platte and Opelousas, but this possibility is strongly 
suggested. 
Southern Louisiana.—There is a northwesterly trend of magnetic 
“highs” from Morgan City to St. Martinsville; this trend perallels 
a line through the Five Island domes, about 20 miles west, and may 
correspond with the so-called Iberian structural axis. 
No continuation of this trend beyond St. Martinsville can be 
preceived from the vectors. An east-west trend of magnetic ‘‘highs” 
from St. Martinsville to Lake Charles, however, is clearly noticeable. 
This trend passes south of Lafayette, northeast of Crowley, north 
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