During Crew 15's rotation here at the MDRS we performed 12 EVAs, two initial training EVAs followed by ten EVAs dedicated to geological exploration and sampling. This record is very good for a crew with only one geologist because there were numerous research projects ongoing, and also because there were many maintenance issues that required our attention.

During the course of these geological EVAs we ranged from the Hab by foot and ATV over an area extending approximately 7 kilometers north, 4 kilometers south, 4 kilometers east, and 3 kilometers west. We traveled up in geologic section to the base of the Ferron Sandstone beneath Skyline Rim and down in section to the Summerville Formation in Candor Chamsa Canyon. We explored and investigated the various members of the varied Morrison Formation and the distinctive Dakota Sandstone. Through our work here we have gained a wonderful understanding of and appreciation for the rocks in the MDRS area, rocks which record the time which brackets the Jurassic/Cretaceous boundary.

We have collected a suite of samples from the sandstone and conglomerate units in the area and have plotted many outcrop locations on a paper copy of the Skyline Rim 7.5 minute topographic quadrangle. We've also noted these locations in NAD27 UTM coordinates throughout my geologic reports. In addition, we have collected several interesting samples of various lithologies as surface float, and we have located (in one place only) evidence of movement along a joint surface, a small fault. Finally, we have made several observations on weathering differences on north-facing versus south-facing slopes.

One of the goals I had for this rotation was to look for perched basalt boulders, which would imply times in the past with vast amounts of surface water. Although we found rounded basalt boulders in modern-day washes, this doesn't necessarily imply any higher flow volumes in the past. A further search for these boulders, especially above the Skyline Rim to the west, would be an interesting follow up. Also, looking forward, a study attempting to establish evidence for joint control of some of the drainages would be very interesting. Also, a look at why the Lower and Upper Blue Hills levels are more dissected in the north than in the south would be worth taking, although this would necessitate several overnight or longer term EVAs, which would be worth doing in themselves.