Stacy Sklar and myself took an "out of SIM" EVA to search for endolith and concretion sites around the general vicinity of the Mars Desert Research Station (MDRS). Our EVA lasted roughly 2.5 hours. Our first site of interest was that of NAD27: 517800 E, 12 424950 N; along the MDRS ridge within the Dakota SS (Sandstone) Formation. Our GPS instrumentation (both Stacey’s and mine) are not working properly, therefore, we need to get in touch with our HSO Officer (who is currently not feeling well) and see if we can borrow her GPS. Therefore, I would strongly recommend not paying too much attention to our site coordinates, but, I do feel obligated to give you the coordinates we read from the instruments. We were in search of finding the site where Melissa Battler initially had found concretions but, we could not find it, due to our poor instrumentation. We then went in search for our own concretion site(s) and came across a nice location with some amazing straitigraphy (which I plan to map later on this week). I noticed right away that the concretion layer(s) were of different size distribution and frequency. I took some sample (remember our "1 in 20" rule that we "shall only take one specimen for every 20." This is a very excellent example we should all follow for, as I tell my students and all those to whom I take out in the field: "Rocks are like flowers...we can pick a few for ourselves BUT...we should leave the rest for others to appreciate".

Concretions near the MDRS	Concretions in host rock. Notice the concretions with a nucleus.
Brachiopods from the Cretaceous period found by Veronica Ann.	Burrows from the Cretaceous period from by Veronica Ann.
Concretion diameters range in many different sizes.	"Comet tails" found within the host rock associated with the concretions and the direction of water flow tell the geological history of this region. "Comet tails" have also been observed on Mars but it is unclear whether aeolian, fluvial or both processes produced these features.

Later on tonight and throughout tomorrow, I will measure the difference in the diameter of the concretions and their distribution within the samples I have collected. When I go on EVA again, I will take the same measurements within the host rock.

Also, to my surprise, I found some brachiopods that are from the Cretaceous period. I picked a wide variety of sizes to which I plan on donating to Arizona State University for educational outreach for others to appreciate and study.

Stacy was in search of endolith specimens within the Dakota Formation, she located two samples within a few meters of the concretion site but is awaiting verification from the RST. Once confirmed she will begin to map the area surrounding both concretion and endolith sites in order to understand the relationship between these two possible biological regimes.

To all of you on "The Good Earth" I wish you good night. We look forward to another productive day tomorrow and cannot wait to share the wealth of knowledge we are obtaining here...on Mars.

Ad Martem!