The following is my translation of an article called: Erdgeschichtliche Zeiträume, Eine geologische Umschau von Dr Kurd von Bülow. It appeared in a German popular science magazine, Kosmos Handweiser für Naturfreunde 1921, Heft 6, Seiten 141-145.
The dates based on early studies of uranium-lead ratios have stood up reasonably well. The age of the Earth, however, turned out to be about 4.7 billion years instead of approaching infinite. Over forty radiometric dating methods are now available, and the technology is both better understood and vastly more sensitive.
I'm not aware of any previous translations.
Trevor Dykes.

The ages of the Earth, a geological review by Dr Kurd von Bülow
Infinity, a word that is unclear to our imagination, an idea created be the cogitating human spirit, defined by this spirit as an aid against incompleteness; an incompleteness similar to that of an infuser that makes a single drop appear as a world without limits.

Our infinity has two aspects:
Astronomy allows us to perceive the infinity of space. "Our Earth, the scene of our world history, the centre of our thought and actions, is a small, dark starlet that quietly follows its orbit between massive, glowing suns. And if the harmony of the spheres were to sound in loud chorus -then no ear would be able to hear the tone of our planet among them" (Walther). That is the space that astronomy has to measure. But even the largest scale, the light year, can only make the vast distances comprehensible for arithmetic, but never imaginable.

"The infinity of time, however, the grandiose, as it appears to us, beengende (?narrowing) and uplifting realisation that each drop of water and every grain of sand is involved in a world forming series of causality, going on everywhere around us", lies just as far from the human capacity for understanding, in which "millions of years" can only be brought into a mathematical expression -the science of the state and development of our Earth is the concern of geology.

Modern geology is thoroughly based on a foundation of actuality, ie, it attempts to precisely observe the earthly surface of the present so as to find the key to the active forces of its formation, so as to gain the understanding of the geological features and structures of the past, and thus the formative processes during the past of our very planet. This is based upon the assumption that the same forces were active from the point of origin of the Earth as today, and these produced the form of the surface of the Earth.

Furthermore, it is one of the prime challenges of geology to understand these forces both in general and detail, in other words, to investigate the water in its various forms and conditions of aggregations, the movements of the air and the organisms, and their effects upon the surface of the Earth (the external dynamics) and, on the other hand, to also research the interactions between the unknown core of the Earth and the crust of the Earth (internal dynamics: volcanism, earthquakes, mountain building, etc).

An end would only be reached by the indefatigable will to research should these challenges for geology all be fulfilled. The immeasurable quantity of wonders and puzzles our Earth provides give rise to entirely new challenges.

When geology recognises the long finished works of eternally active natural forces among the colourful transition of the rock layers, then it is attempting to produce a picture of a part of the Earth for a particular length of time, that is impregnated in the neighbouring places and the stratigraphy of the layers deposited chronologically one after the other.

This enables geological research to find a method of dating ages, albeit at first only limitedly.

These stratigraphic methods of dating, as science terms it (after the Latin stratum = layer), grew and soon found a loyal and valuable partner in paleontology, and that in the remains of plants and animals delivered to us by the rock layers, the fossils.

With the realisation of the fact that, since the first appearance of organisms, there has been a gradual and uninterrupted development through the entire span of geological time, the fossils have not only been of irreplaceable value for the comparison and interpretation of rock strata, but they have also served as pronouncements for the succession of great episodes in the history of our Earth.

The 'German Triassic' provides an excellent example of this as, for this Mesozoic Formation with its three subdvisions, deposits cover large areas of German ground: On top of the Buntsandstein, which is distinguishable by its colour, wind traces, animal tracks and salt deposits, and was mainly the result of deserts, are immediately found the mighty layers of the Muschelkalk, the name of which informs of its origins as marine deposits, and then comes the Keuper with its continental conditions characterised by dried out, reed rich lakes and swamps. (Translator's note: 'reed' can't have been meant too literally. None are known among the Triassic fauna, as they don't appear to have been invented.)

This working principle of actuality inherently gives rise to the attempt to gain secure and complete numerical information for global events which, until now, could only be done to a limited degree. It is similar, for example, to subdividing history according to the succession and years of reign for rulers, so as to learn about the wider historical framework, and also provides the possibility of measuring their chronological distance from each other and ourselves.

And so we would certainly like to know: How old is this coal? When did some creature live, whose remains have been provided by the rock strata? How long is it since people ceased to be animals? How long...? and so on.

If I know how a stone has arrived in its present condition, then I only need, if possible, to follow that process which today still produces such rock, and only need to observe how long this process might require, and I would obtain a more or less precise timescale for the same effects for these events in geology.

A few examples:
Much of our sedimentary rock originated as oceanic deposits, such as the Devonian Eifelkalke and the similarly aged shales of the Middle Rhein Mountains, the rocks of the Carboniferous Formation in many areas of Germany, the Zechstein with its rock salt and crystal salt deposits, the Muschelkalk and Jurassic strata over almost all of Middle and especially Southern Germany, the Cretaceous and part of the Tertiary. If I know that similar deposits today accumulate at a rate of only 10mm per year, then I am close to being able to calculate how long a 7000m thickness of a similar rock required in earlier periods. But I must not forget that it is impossible to learn all the depositional conditions in a stratum, and I must take that into account in my figures.

1000mm of Blausand -a shallow marine deposit in the Coral Sea of Eastern Australia- builds up in the same timescale as 20mm of Globigerinenschlick* in deep water, or as 9mm of red deep sea clay. All three sediments can be unnoticeably combined, and that means it can be unbelievably difficult to say: the border is here. It is naturally even more difficult to establish during which period of time this or that compressed, transitionary sediment built up. Mostly, we require the help of tolerance figures such as, for example, a rock required between 200,000 to 2,000,000 years to form.

(* Globigerinen are organisms with chalk shells from the group of the so called Foraminfera.)

Nevertheless, this method has provided a reasonable understanding, but it must always be remembered that only approximate values are possible! This technique can be employed for a number of types of rock:

Guano, massive piles of bird and seal manure on rain-poor, tropical islands, can build up to depths of 10m within 1,100 years.

Coral grows on the outer side of a reef at around 0.5 - 1cm each year, on the inner side, however -due to the shortage of fresh water and food- 10 to 100 times more slowly -therefore, one must be careful when calculating the time required for coral structures.

This method of actuality has, through the history of geological study, led to ever larger numbers, when one attempted to gauge the age of the Earth. Whereas, earlier, one came to 10,000 to 100,000 years (one reached such figures be letting, for example, glowing balls or iron cool), one already reckoned 14 to 120 million years a few decades ago. But even these numbers are far too small for the real conditions, as they have been further revealed to the sight of researchers from day to day.

In the cases mentioned, the estimates were based upon totally unsafe fundaments, but this is very different -and more convenient- if we turn to the geology of recent time, and observe the processes that still operate today. "Geology of recent time" refers to the period of the Alluvian, which is presently underway, when the German land was freed of Diluvian inland ice, as the rays of a warmer Sun made the ice retreat north and south; it is, in a phrase, the post Ice Age, and it contains the largest share of human prehistory and all historical time.

One can use the effects of streams and rivers for assessing time, as these are easy to calculate; but one does not know whether an insignificant channel of today was not previously filled with a greater mass of water.

One has calculated how many years the Niagara Falls -since the Ice Age- have required to reach their present position from Lake Ontario, if -as today- it has moved back annually at 1.2 to 1.5 metres.

One has utilised peat deposits for calculations. As is known from many observations made on many occasions, living high bogs (see Kosmos 1920) lay down a peat layer of 0.5 to 1mm per year and, accordingly, the age of a peat bog can be precisely determined in terms of years. Remains of human culture, which peat bogs are so rich with, can be reliably dated to a certain degree and compared with other discoveries, or also set into connection with other cultures for which, as for example the Egyptians, we have exact dates going far back into European prehistory.

Geological developments can also be specified from bog geology. An example is the Litorinasenkung on the coasts of Vorpommern** which, it has recently been shown, has an age extending back to 6,000BC, and that is most of historical time.

(** Land movements following the Ice Age -thus during the Alluvian- have caused the largest part of the North German coasts to sink by 5 - 20 m. The name refers to a small muscle found in the deposits from the earlier sea ('Listorina Sea'), akin to an enlarged Baltic Sea, which have been left behind in the coastal area; it is Litorina litorea.)

At a distance of about 50km from this place one can assess the time of the sinkage by another method, and this showed it had ceased at Swinepforte (the middle estuary of the Oder) by 5,000BC. And Keilhack was able to research this area by comparing older Swedish and recent Prussian maps; he found that each of the very regular sand dunes at Usedom and Wollin needed 35 years to be established.

As the oldest of these dunes could only first have developed after the sinkage, its age of origin tells us something about the end of the land movement.

But all these very precise calculations only provide approximate information, as one does not know all the potential sources of errors and, should they be known, then they cannot be taken fully into account!

It is somewhat different with the surprisingly simple and reliable process discovered and developed by the Swedish geologist, De Geer, and left nothing further to be wished for. As this allowed the first absolute assessment of dating, it should be briefly addressed:
The Diluvian Ice Age left all of North Europe covered by a massive continental ice sheet from the centre of Scandinavia. As the climate became warmer and the ice masses melted, all the material it had supported and carried along -as today occurs, for example, in Greenland, came to the ground; rough blocks remained on the spots where they fell, the finer sands were taken by the melt water streams, and transported for some distance from the glacier, and the finest river dusts went yet further -into the Ice Sea, in the position of today's Baltic Sea, on the edges of the ice sheet- and was deposited as a clay mud. Summer after summer, as the heat of the Sun burned down, and the relatively high temperature allowed for a lively oxidisation, the light chalk coloured mud settled in large quantities.- Winter after winter, darker and thinner 'bands' were laid by the slower thawing of ice on the top of the summer strata, and this took place regularly.

Each layer with a light and a dark band means a year!

When this was eventually recognised, it was only necessary to count the individual strata -and one had precise figures concerning the speed of retreat for the northern continental ice, and the length of the post Ice Age in years!

De Geer carried out systematic investigations in Sweden, and found out that the retreat of ice from South Sweden to the present ice shield in North Sweden had taken 5,000 years. The ice had retreated 50m a year in the south, and 300m in Central Sweden.

By a simple process of analogy, also confirmed by Danish research, Germany was not yet free in the year of 10,000BC during the last -the fourth, according to recent investigations- Ice Age.

Matti Sauramo conducted similar research in Finland: The ice sheet retreated from the north coast on the Finnish Bay to the southern edge of Salpaußelkä within 9 centuries, a double bank of moraine arcs as a border through the Finnish lake zone, the Land of the Thousand Lakes, to the south. It remained there for over 100 years, and after 300 years had reached Nordwald, where it stopped again for 200 years: In the year of 1522 it had moved back a further 100km!

Due to this clay band method of De Geer's, Diluvian geology has become a reliable calendar, and it is similarly gratifying that still older earthly history has found a reliable ally in the radium research. This newest chapter of chemistry should also be a breakthrough in the field of geology!

It is known that the element uranium breaks down at a regular rate and constantly changes into other elements. It changes, among others, to radio-uranium, ionium, rodium; further to emanation, helium, radio-lead, polonium and lead. Uranium is found in many minerals of granite, syenite, pegmatite (in some of the massive stones!) and, for example, in Aschynit, Gadolinit, Monazit, Uranglimmer and especially in the Pechblende, the starting point in the production of radium. As no link in this uranium chain is inert (the lifespan of the single links varies from a few seconds to some thousands of years!), one would expect to find always more members of this decay process in a bechblendeführenden rock, for the longer the process lasts. And this assumption is actually fulfilled. Furthermore, one finds that the undecayed materials between uranium and radium are in a state of balance which none of these materials can dominate or escape. -As uranium decays via radium into helium, and then finally to lead, and the annual rate of the production of helium from uranium is known, one could easily read the age of the mineral in years from the proportional quantities of helium relative to uranium. However, a condition is that all the helium present in the mineral must only have originated from the uranium, that is that no helium may have originally been present in the mineral, and that no exchange of uranium and helium has taken place between the material under examination and its surroundings.

As one cannot test the correctness of these required conditions, especially as one does not know whether all helium has remained in place and is available for measurement, one only receives a minimum value from this process.

However, if one takes the relationship of uranium and lead into account, that is much robuster and securer than helium gas, one receives much higher values, and one may perhaps see these as being maximum values.

The average ages of a few important geological formations, according to these lead measurements, are as follows:
Precambrian 1,100-1,600 million years
Silurian 430 million years
Devonian 370 million years
Carboniferous 340 million years

The corresponding "minimum values" of the helium method are only 145 for the Devonian, for the Carboniferous (the age of much coal) only 141 million years. For the oldest part of the Tertiary, the Eocene, the result was 31 million years.

We are at the end. We have quickly introduced a few important methods for measuring geological time. We saw that this field of the broad science of geology is just beginning to reach the stage of exact research.

Certainly, the results of modern radiometric dating are controversial and disputed -but a secure path is opening there: Soon, we will know more about the age of our Mother Earth. Soon, we will be able to replace impressive assumptions with exact numbers.

Nevertheless, there is something that we can already say: We are looking at a lifespan of 1,500 million years -at the start of this span, highly organised organisms already existed. The path that life had followed from the first clumps of slime to these forms was surely 100 times, or a 1,000 times longer, than the path between the oldest known Precambrian crabs, that lived on the sea bed one-and-a-half-thousand million years ago, and led to us, the human!

And before the Earth globe had cooled sufficiently from a fiery, liquid state, so that liquid water could rain down upon it and could fill its depths, so as to allow the first slime clumps to arise and be sustained -that time was endlessly much, much longer.

And when we compare the age of the Earth with that of a year, and if this year has a second representing a million years, then the crabs of the Precambrian appear at half-past eleven during the night of New Year's Even, and as the first stroke of the bell signals midnight, the animal became people---
"Wise sailing phantasy,
Cast me a weak anchor.
Human perceptions fail.

Nevertheless, the racing spirit will also translate this wonder into cold numbers and orderly formulae in a none-too-distant hour, the words of endless time -but it will not be able to remove the magic of this wonder.

As the uranium-lead figures for years give are averages, they should fall within the cited periods. They don't purport to represent any particular sector; eg. a beginning, middle or end. According to present understanding, they all do fall within the target which, at the time of aiming, was undefined in absolute numbers.

Translator's note:
That final sentence is a tempting challenge to present understanding.
The dates stated for the Precambrian, 1,100 - 1,600 million years, are Precambrian. The Silurian (430 my) is in the Silurian, the Devonian (370 my) is roughly in the middle of the Devonian, and the Carboniferous (340 my) falls within the Carboniferous.
Most of a century has gone by, and Dr van Bülow is still winning 4-0.

An index of more of my translations of old Kosmos articles can be found at:

Kosmos Translations Archive

A number of Mesozoic (and post-Mesozoic) location summaries can be found at Localities.