52 E. E. ROSAIRE AND O. C. LESTER, JR. 
By virtue of their being first to embark upon this virgin field, these 
two refraction crews staged what is probably the most spectacular 
campaign in the history of geophysical exploration, discovering no 
less than eleven salt domes in 9 months. These successes, starting 
similar campaigns by other companies, caused the intensive explora- 
tion (by seismograph crews) of southeastern Louisiana, and further 
resulted in the discovery of six additional salt domes in this same 
area, all within a year after the discoveries of the Calcasieu Lake 
and Vermilion Bay salt domes. 
2. This successful application of the seismograph to water ex- 
plorations undoubtedly brings part, at least, of the Gulf of Mexico 
within the available petroleum reserves of this geological province, 
if or when the value of crude oil justifies the solution of such practical 
and legal complications as are apparent. 
OPERATIONS 
Vermilion Bay varies in mean depth from ro to 13 feet in an area 
of approximately 125,000 acres (Fig. 1). The operations in this in- 
stance, as in other water explorations of similar magnitude, were con- 
ducted entirely from boats. The crew was quartered in a houseboat 
with auxiliary barges for explosives and supplies, while the recording 
apparatus was mounted in fishing luggers 40 to 75 feet in length. A 
similar lugger was used in locating, planting, and firing the charges 
of explosives. 
The explorations were conducted by the usual method of refrac- 
tion fans. Communications and transmissions of time signals were 
effected by two-way radio operations on 180 meters, using 5-watt 
IC Wtransmitters. Distances from shot to recorders were determined 
from the air travel times of the explosive sound waves. 
Though the analysis of such exploration data is comparatively 
simple, its acquisition involves the solution of many practical difh- 
culties. Adverse winds may carry the sound wave above the recorders, 
or may lower the water level to such an extent that operations of any 
kind are impossible over the subsequent mud flats; and may even 
maroon the recording boats for as much as a week. In the latter case 
the resulting diet of canned tomatoes and oysters becomes rather 
monotonous after a few days. On the other hand, moderately rough 
water is no great handicap, since seasick observers have taken excel- 
lent records with the seismographs planted in water and mud at 
depths of 15-20 feet. Also, as this coast is not infrequently visited 
382 
