Field of Science

Happy Easter with a (fake) Dozen Dinosaur Eggs

Roy Chapman Andrews was not only an intrepid explorer and palaeontologist, but also a gifted promoter. The Central Asiatic Expeditions in search of fossils of mammals and dinosaurs were accompanied by movie cameras to film their work. As the conditions were most time prohibitive -sandstorms, burning sun and arid climate - many scenes showing the discovery and excavation of fossils were probably staged after the real work had be done.

Many photos of the expedition-photograph John B. Shackelford show dinosaur nests filled with "Protoceratops*"eggs (*in fact Oviraptor eggs), superbly preserved. It seems unlikely that the eggs were in such good shape when first discovered. More strange is the common notion in popular culture that the nests contained exactly a dozen of eggs, believe probably influenced by photos of reconstructed nests.
In fact in Andrews's descriptions the number of eggs per nests varies, from three to nine, only in one case he mentions thirteen eggs, however embedded in a block of sediment.

Fig.2. Original 1923 photograph of dinosaur eggs found at the Flaming Cliffs. Fig.1 from True Comics #81, Parents’ Magazine Press (1950).


DAVIDSON, J.P. (2008): A History of Paleontology Illustration. Indian University Press, Bloomington: 217

Tiny Plants Creating Big Rocks

Often enough the rocks determinate the presence and distribution of plants (as shown in the wonderful blog "In the Company of Plants and Rocks"), but sometimes it's the plant shaping the rocks. 

Plate showing the deposition of travertine* around single algae cells (ca. 1935). The high content of carbonic acid (white circles) dissolves carbonate (shown as schematic rhombohedra-crystals). Plants (like this alga) use the carbon dioxide for their metabolism and the water becomes less acid, the carbonate is deposited around the plant tissue. The final figure shows the soft water, with less dissolved carbonate.

The upper caption reads: 
"Tiny Plants
built the Travertine of Polling**
Substance in the water, they found
Sun gave them power"

This plate was drawn by the German Prof. Dr. Gustav Dunzinger (1868-1940), pharmacist and plant-physiologist. Dunzinger dedicated himself also to scientific-botanical illustrations.

Fig.2. Outcrop with travertine investigated by Dunzinger, old quarry near the German village of **Polling.

*Travertine is the general term in Germany for continental limestone, however in English it is referred to limestone from hot springs or deposited by inorganic processes. Calcareous tufa forms by precipitation of calcium carbonate from “cool” springs and river waters, helped by organic processes - the travertine of Polling is therefore a tufa.

Newton's Alchemy and early Geochemistry

Sir Isaac Newton (1642-1727) is today remembered for his contributions to optics, mechanics and gravity, but as a typical polymath of his time he was also interested in alchemy. And through his interest in this early predecessor of chemistry he became also involved in some geological research.

The theologian and naturalist Thomas Burnet submitted an early draft of his "Telluris theoria sacra" to Newton in 1680-1681 and Newton exchanged with Burnet some thoughts on the formation of the rocks, mountains and the earth. Based on his observations of crystallization of molten tin and saltpeter from water, but also curdling of milk when beer is added to it, Newton imagined earth's matter somehow crystallizing from the primordial, undifferentiated chaos.

Newton never published in full his geological ideas - but some surviving notes deal with (early) geochemical concepts. Two notes, dated to 1670, entitled "Of Natures Obvious Laws & Processes in Vegetation" and "Humores mineralis" deal with the "sal nitrum" theory.  The crystallization of saltpeter, or potassium nitrate (KNO3), is easily observable both in nature as in the laboratory and it was considered by many naturalist of Newton's time as ideal model to understand mineral growth and finally the genesis of ore veins in mountains. 

Alchemy regarded saltpeter even as a sort of philosopher's stone, able to transform into other minerals.

Fig.1. "The Alchymist, In Search of the Philosopher’s Stone, Discovers Phosphorus, and prays for the successful Conclusion of his operation, as was the custom of the Ancient Chymical Astrologers", by Joseph Wright of Derby (1771).

This transformation could explain why minerals were abundant on earth, despite the perpetual dissolution by groundwater percolating into the underground, Newton explains in "Humores mineralis":

"with the metals continually drawn downwards, never ascending so long as they remain metals, it would be necessary that in a few years the greatest part would have vanished from the upper earth, unless they are conceded to be generated there de novo."

The term "vegetation" in the title of Newton's other note refers to the idea of a spontaneous force generating
new metals in the centre of earth and injecting them into earth's crust - alchemy considered principles influencing the inorganic nature very similar (or even identical) to life processes. It's therefore no wonder that Newton describes fluids and vapours ("spirits") mating in earth's crust to give birth to the progenitors of metals:

"Indeed, these spirits meet with metallic solutions and will mix with them. And when they are in a state of motion and vegetation, they will putrefy [and] destroy the metallic form and convert [it] into spirits similar to themselves. Which can then ascend again and thus a perpetual circulation of metals takes place."

These progenitors derived from
saltpeter, especially sulphur and mercury as most important elements in alchemy, will continue to migrate to the surface, where they transform and are deposited as other useful metals. Such metaphysical explanations for the origin of rocks will prevail for a long time in history.


NEWMAN W.R. (2009): Geochemical concepts in Isaac Newton's early alchemy. In Rosenberg, G.D., ed., The Revolution in Geology from the Renaissance to the Enlightenment. Geological Society of America Memoir 203: 41-49