DETAILS OF THE DEVELOPED TERRITORY. 
99 
The first oil zone (A), which lies from 250 to 500 feet above zone B, 
is struck at depths ranging from 1,400 to 2,450 feet. Its thickness 
ranges from a few feet to about 50 feet; according to the logs it is 
lacking in some of the wells, the first oil being encountered in zone B. 
The oil-bearing strata in zone A are largely shale, which afford a 
reservoir for the oil, probably on account of their fractured condition. 
Beds of fine sand in this zone may also contain some of the petroleum. 
The second oil zone (B), occurs at depths of 1,950 to 3,150 feet 
and is penetrated by all of the wells in this area. It ranges in thick¬ 
ness from nearly 50 to about 250 feet, in the wells; one of the wells, 
however, is- said to encounter petroliferous beds intermittently from 
the top of zone B for a distance of 550 feet downward. The oil¬ 
bearing strata consist of alternating layers of hard shale and fine 
sandstone. 
The third oil zone (C), occurs from 500 to 600 feet lower in the 
wells than zone B and consists of two parts, each from 25 to 50 feet 
thick, separated by a layer of shale of variable thickness; in one of 
the wells, however, the intervening shale is missing and the strata 
are richly impregnated with oil from the top of the zone for a distance 
of 250 feet downward, to a point where a 3-foot layer of water sand 
limits the productive zone. In practically all the wells in the field 
zone C is very rich, and nearly all the wells tapping it are fine pro¬ 
ducers. 
PRODUCT. 
The oil obtained in the area under discussion averages somewhat 
better than that in the area to the east, and has a gravity of 26° to 28° 
Baume, with an average somewhere between 26° and 27°. As is com¬ 
mon in other portions of the field, the gas pressure in most of the 
wells is high. 
The production of the individual wells ranges from 100 to 2,700 
barrels per day, the well yielding the latter amount being said to have 
had an initial daily output of 5,000 barrels for a short time. In one 
series of wells those down the dip are more productive than those 
nearer the axis of the anticline, the variation being at least partially 
accounted for by a thickening of the oil zone away from the axis. 
HARTNELL BROOKSHIRE AREA. 
LOCATION AND STRUCTURE. 
The area comprising the southern portion of the Hartnell tract 
and Brookshire property and the southeastern portion of the Radium 
lease is located on or adjacent to the ridge running northwestward 
from a point near the west end of Graciosa Ridge, and in the broad 
valley to the south. The major structural feature developed in the 
