20 OLAF F. SUNDT 
in Wharton County, where a maximum extends due south of the 
producing high wells, where there is a sharp drop from a rather flat 
subsurface top to the structure. There is no evidence that the Louise 
is a salt dome. If so, it must be very deep, since wells have been drilled 
deeper than 7,000 feet without encountering salt. 
Undoubtedly the four greatest discoveries by the torsion balance 
are Sugarland, Rabbs Ridge, Manvel, and Iowa—greatest at least 
from the economic standpoint. 
Full credit for the discovery of Sugarland is given to the North 
American Exploration Company crew working for H. C. Cockburn. 
The area had been shot over by refractions several times without 
being found until the torsion balance showed indications of a mini- 
mum. Further refraction seismograph work confirmed the dome. 
The Rabbs Ridge dome was found by crews of the Gulf Production 
Company. Early torsion-balance work gave vague indications, but 
detailed work in 1929 and 1930 confirmed the presence of a deep- 
seated salt dome. The picture is not well defined. Lack of permits for 
work on the southeast necessitated interpolation of isogams over 
large distances in order to effect the necessary closures. Averaging of 
gradients was necessarily used to a great extent where irregularities 
were caused by surface and near-subsurface depositional variations in 
the Brazos River bottoms. Stations were made very close together. 
Calculated sections across the gravity anomaly (Ag section) show defi- 
nitely that Rabbs Ridge is a deep-seated salt dome rather than a part 
of a regional trough. In that respect, it was also noted that the axis 
of Rabbs Ridge was not in the direction of the known regional trends. 
The Manvel dome was discovered for The Texas Company by the 
Torsion Balance Exploration Company. Good interpretation was 
shown in outlining a dome represented by very little closure and 
hardly any on one side. The actual producing area is south and south- 
east of the minimum. 
Of the other domes listed, Esperson, discovered for the Union 
Exploration Company by Christian Iden, and Citrus Grove, a Cock- 
burn discovery, are well marked minima. 
Hankamer, Chambers County, a Gulf Production Company 
discovery, stands out fairly well, although obscured on the west 
side by the strong influence of the shallow Moss Bluff dome. 
Garwood, Colorado County, was discovered by the Torsion Bal- 
ance Exploration Company for the Coyle-Concord Oil Company. 
Livingston was discovered by the Sloane Prospecting Company and 
later confirmed. The Shell Petroleum Company discovered Lakeview, 
where two wells were drilled showing gas and some structure. 
Tomball is a discovery by the Vacuum Oil Company and the 
680 
