The question of the importance of using the base cation saturation ratio concept (BCSR) in the nutrition of crops and for making soil test recommendations have been raised many times over the past 100+ years. Recently this issue has surfaced again as a part of programs promoted as “sustainable farming systems” or friendlier to the land or other parts of the environment. As others before them, t...

A new sclerosponge, Acanthochaetetes wellsi, with a calcitic skeleton made up of contiguous vertical tabulate calicles ornamented within by vertical rows or irregular clumps of spines is described from cryptic habitats on reefs in the western Pacific region. A lamellar microstructure characterizes the calicle walls and spines. Increase in number of calicles occurs as intramural offsets. An epit...

Sea urchin teeth grow continuously and develop a complex mineralized structure consisting of spatially separate but crystallographically aligned first stage calcitic elements of high Mg content (5-15 mol% mineral). These become cemented together by epitaxially oriented second stage very high Mg calcite (30-40 mol% mineral). In the tooth plumula, ingressing preodontoblasts create layered cellula...

Much of what we know about the history of Earth’s climate derives from the chemistry of carbonate minerals in the sedimentary record. The oxygen isotopic compositions (dO) of calcitic marine fossils and cements have been widely used as a proxy for past seawater temperatures, but application of this proxy to deep geologic time is complicated by diagenetic alteration and uncertainties in the dO o...