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Richard Squires
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Retired professor of paleontology and geology
Retired professor of paleontology and geology

17 followers
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A 50-million year old chambered nautiloid shell
The living "pearly nautilus," also called the "chambered nautilus," is a favorite seashell of many collectors. Today, the biodiversity (number of species) of these animals is very low, and they are confined to tropical waters in the equatorial region of the...
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Colors of scallops
If you have been reading my latest posts, you will know that I have been focusing on colors in certain minerals. In this present post, I shall discuss colors of certain clams called scallops, which belong to the family Pectinidae. The family is comprised of...
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Barnacles make interesting fossils
Barnacles are classified as cirriped crustaceans and  belong to phylum Arthropoda (a large
group that also includes trilobites, crabs, insects, etc.). The name "cirriped" ( cirri , curl; ped , foot) refers to the six pairs of delicate appendages which are
u...
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Colors of fluorite
The mineral fluorite consists of calcium fluoride (CaF 2 ). It can have variation in color, largely due to impurities in its crystal structure. Flourite can be found throughout the world. It is common in hydrothermal deposits, where it can be associated wit...
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Copper and Molybdenite
COPPER   (Cu) is a naturally occurring pure element with a
reddish-orange color. This is the element copper in its pure natural form. The specimen, which is 5 cm long, shows the dendritic habit of copper. The gray material is gangue (wall rock) material con...
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Some varieties of the mineral gypsum
I decided to do a post on the mineral gypsum just after my previous post on calcite because the two minerals can resemble each other.  Gypsum is a very common mineral and is the most common sulphate mineral. It forms as an evaporite mineral and is commonly ...
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Calcite and some of its interesting properties
The mineral calcite consists of calcium carbonate CaCO 3 . It is a very common mineral that makes up limestone. Beginning students in geology labs quickly learn that calcite can be easily identified because it fizzes in weak hydrochloric acid. Also, if the ...
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Eocene oyster Cubitostrea sellaeformis
If you have been a reading my posts for the last three years, you will know that I have a strong interest in fossil oysters. I return to them with this post, which concerns the middle Eocene (about 45 million years old) oyster Cubitostrea sellaeformis  (Con...
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Two Late Cretaceous species of the bivalve Pterotrigonia
In some cases, recognition of two species of the same genus
can be problematic. In the examples shown here, however, the recognition  is straightforward.  The species are of a shallow-marine bivalve (clam) of Late Cretaceous age from the west coast of North...
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"Desert Roses"
“Desert roses” are clusters of crystals of
baryte or gypsum containing inclusions of sand. “Baryte” is the new official spelling of the
mineral barite. The radiating-outward “petals” form when flat baryte or gypsum crystals, which precipitate out of shallow...
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