Our  Featured  Specimen

Updated 5/19/2012

WELCOME TO MILLS GEOLOGICAL

specializing in unusual, identified petrified wood

and plant fossils from around the world

We invite you to click on any photo to see a larger, more defined photo of the select specimen. For a more complete listing of our specimens, please download our catalog from from the links below.

Thanks for your continued loyalty!

Jim and Beth

Root Cast Mass in Matrix

San Miguel County, Colorado

**  Fascinating specimen of rather long rootlets massed in a welded-tuff matrix.  All of these rootlets are agatized casts and therefore do not have sufficient structure to determine taxonomic affinity, but they do offer an intriguing view of rootlets that must have been exposed to the air when they were covered by very hot volcanic ash and debris.  Be sure to click photo for a closer view.

4" x 3" root mass; 1.5" thick. 

Individual rootlets vary in diameter from 1/4" to 1/2"   $42

Cherry (Prunus sp.)

Bretz Mine Airport Site, McDermitt Nevada/Oregon

** Ahhh...we just love these main limbs with a separate branch coming out at the side! This Cherry has an exquisite second center at the 9:00 position where the branch is leaving the main limb.  The Bretz Mine was a Mercury mine in the mid-19th century and the airport was a gravel strip to enable executives and specialized technicians to fly into this remote part of northern Nevada and southern Oregon.  These days, only rockhounds and hunters visit the area and the airport is barely visible but the name persists as a locality reference for diggings (some of which go down 14 feet) of fine petrified wood specimens.  Another interesting fact: the site is actually related to a giant volcanic caldera that was active during Miocene times (Trout Creek Formation) and which produced the mercury that was mined as well as the wood that is still collected. 

7" x 4.5" on polished face; 1/2" thick slab    $47

Blue-green Algae Stromatolites 

(Collenia undosa)

Biwabic Iron Formation;  Lower Chert Member

Precambrian 2.2 billion years old

Biwabic, Mesabi Range, Minnesota

**  At 2.2 billion years old, this is definitely the oldest stromatolite to have been found in the US, but perhaps not the oldest on record worldwide.  Once called by the common name "Blue-Green Algae," the Collenia genus is now classed as a Cyanobacteria.  It is theorized that these early Precambrian organisms were responsible for the release of oxygen from rocks that now makes up the important (to us) part of our atmosphere.  The Collenia are characterized as turbinate growths.  Their life was frequently interrupted by the settling out of silt or precipitation of limestone which covered the growing surface.  The organism would respond by breaking through the silt and then covering it with another complete growing surface.  This is what gives these stromatolites their layered appearance.

7" x 3.5" on polished face; 1/4"  thick slab  $48

Redwood   (Sequoia sp.)

Stonewall Pass, Esmeralda County, Nevada

**  WOW!  This is, by far, the very longest limb section we have ever had from the classic Stonewall Pass locality.  At nine inches, it is at least three times the length of the longest we have ever had in our inventory.  The exterior wood grain character is excellent, and the cut and polished face shows some ouitstanding woody fine structure.  This is an important specimen from this locality

***

1.5" diameter on polished face; 9" long limb section  $85

Hemlock  (Tsuga sp.)

Tertiary

Bradshaw Basin, near Challis, Idaho

**  The definition of the growth rings is really quite wonderful on this great Hemlock log.  The strong definition is caused by the abrupt change in the size of tracheids between spring wood and summer wood.  Under the microscope, the two show up very distinctly.  The difference in tracheid size is so dramatically different and the transition so abrupt that it almost looks like there are two different growth rings (but it takes the two of them to make up a single annual cycle). 

Bradshaw Basin is not represented in many collections.

If you don't have a piece from this locality -- or a Hemlock -- this is your golden opportunity!

4.5" x 4" on polished face; 1/4" thick slab   $59

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