Maths in Paleontology (I): Data

''In every special doctrine of nature only so much science proper can be found as there is mathematics in it.'' - Immanuel Kant, Metaphysical Foundations of Natural Science (1786)

Warningly the maths professor who got the unthankful task to teach us first-semester scientists-to-be some basic basics of his field chose Kant's statement as the first in his first lecture on "higher" maths. However, when I started my studies in geology and paleontology, there was another saying among old school geology teachers: "A bad mathematician makes a good geologist."

Many a fellow student were rather willing to believe in these latter words than in the inconvenient alternative. (I always considered this believe as outdated and I got the feeling that geology as a science might have been shaped not only by the talents of its protagonists but also by their limitations in terms of exactness and rigorousity.)

Luckily you were not necessarily considered as a bad geologist if you were interested in maths and the notion that modern geoscience involves maths and exact methods (e.g. methods of quantitative data analysis, databases, multivariate statistics and geostatistics, geoinformatics and geographic information systems, 3D and 4D modelling, remote sensing) was clearly on the rise. Perhaps from a biologists' point of view this story would be different, but, to tell you the truth, some of the biology-based paleontologists I got to know are not much living on the exact side either.

Apart from microscopy seminars, field, and lab practicals which teach you ways of data acquisition some classes in statistics and data analysis during first semesters of study give you an idea about the structure of data and ways how to sample and how to deal with data in order to find new knowledge, e.g. a relationship between two phenomena previously not considered to be related.

At the very beginning you will learn that there are different types of data used in paleontology and that you have to bring your data into shape for any kind of mathematical analysis tools, i.e. arrange them as a data table such as the following:

Specimen	Class	State of XYZ	No. of UVW	size L [mm]	size M [cm²]
A	a	Aa	2	12.1	234
B	b	B	3	13.3	87
...	...	...	...	...	...
X	x	X	...	...	...

Normally lines of the table represent samples (or groups of samples or taxa) whereas columns may represent various features or measures. Such features may be the belonging to a certain class or category or the presence, absence, or specificity of a feature. Measured values as entries may have a discrete contribution (e.g. natural numbers such as the number of teeth or segments or body chambers) or a continuous distribution (e.g. length, area, angle, temperature measurements).

Various data relevant for paleontologists can be arranged as tables, such as morphological and microstructural data, stable isotope and other geochemical data, geographical, sedimentological, and stratigraphic data, as well as taphonomic and paleoecological data. Some of these data have a special structure and can be referred to one of the following types:


Compositional data...

... add up to 100%. Chemical compositions of fossils or faunal compositions are compositional data:

Community	Trilobites	Brachiopods	Echinoderms	Poriferans	Nautiloids
A	23 [%]	42	17	5	13
B	10	15	5	50	20
...	...	...	...	...	...
X	...	...	...	...	...

These data require careful considerations and a special kind of maths because all variables are (necessarily) correlated and thus an alleged dependence, e.g. of brachiopod and echinoderm abundances, can be obscured by variation in another group.


Spatially or temporally correlated data

‘Spatial correlation’ means that values for data points close to each other are more similar than values of more distant data points – e.g. the faunal composition of an ecosystem from Arizona is rather like that of a Nevada community than that of a Massachusetts community.

Locality	Easting (X)	Northing (Y)	Facies	Archosaurs [%]	Rhynchosaurs [%]
A	5687	0487	lacustrine	23	45
B	6485	0808	fluviatile	34	38
C	6800	1490	fluviatile	40	37
...	...	...	...	...	...

Geostatistics is the usual method to deal with spatially correlated data. Spatial correlation can also occur on much smaller scales, e. g. the shape and size of two skull bones in contact to each other can show a stronger dependence than the shape and size of bones that are more distant to each other.

In paleontology temporal correlation is quite abundant, especially if your study considers different stratigraphic ages or sedimentological field data:

Population	Horizon	Ar/Ar age [Ma]	Facies	δ18O [‰]	Average size [mm]
A	1	210 ± 1	deltaic	-2.0	5.2
B	2a	N/A	distal shelf	1.4	6.4
C	2c	207 ± 2	?	2.1	6.8
D	4	200 ± 1	deltaic	-2.2	6.0

As in stockmarket analytics methods of time series analysis can be applied to interpret temporally correlated data (i.e. time series). Such data may be relevant for your study as they often indicate evolutionary trends (biological evolution in the stricter sense but also evolution of paleoenvironments), cyclic processes with a certain periodicity, and/or they can form the basis for relating contemporaneous processes in the geological past (e.g. stratigraphic correlation of separate sedimentary successions).


Orientation data

For elongated fossils such as conical shells or long bones the orientation of the fossil long axis towards the geographical cordinate system can be measured using a compass (with inclinometer). In a similar way the orientation of bedding planes can be documented. Such measurements are often used for the purpose of deducing the former transport direction of a ancient sediment transport and depostion system (such as a river, delta, or alluvial fan). A data table with orientation data may look like that:

Specimen No.	Description	Length [cm]	Horizon	Azimuth>	Dip
1	long bone	21	1	N 20° E	0°
2	rib	12	1	N 10° W	5°
3	calamite stem	80	2a	N 15° E	0°
...	...	...	...	...	...

“Azimuth” refers to the angle towards north. Orientation data are distributed on a halfsphere. Mean values (e.g. the average orientation of long bones) and other distribution parameters cannot be derived directly from the averaging of orientation angles but vector arithmetics has to be applied.


Cladistic data

Phylogeny on the basis of morphology conventionally involves cladistic methods, especially in the field of vertebrate paleontology which deals with a particular character-rich group that is deemed suitable for cladistic approaches employing certain kinds of analysis software specialized for the calculation of phylogenetic trees (e.g. PAUP, WinClada).

In cladistic datasets lines represent taxa, mostly species or genera of the group of interest, and columns represent characters (ordered by number), i. e. features of the skeleton which are variable among the included taxa:

Taxon	1	2	3	4	5	6	7	8	9	10
A-saurus	0	0	0	0	0	0	1	0	?	0
B-raptor	?	0	1	?	0	0	1	1	0	0
C-onyx	1	1	0	?	-	1	-	1	0	1
D-ops	1	1	2	1	1	1	1	0	1	1
E-mimus	0	-	2	1	1	2	0	0	1	1

One of the main issues in cladistics is the definition of characters and the correct (unbiased) coding of morphological information. You can include qualitative differences ("bone X contacts bone Y but not bone Z" = character state “0”; "bone X contacts bones Y and Z" = character state “1”) and quantitative differences ("length of metatarsal 3 larger than or as large as length of metatarsal 4" = character state "0"; "mt3 is shorter than mt4" = "1"). Sometimes mixed character states like "0 or 1 [but not 2]" occur in a taxon and are coded accordingly.


Missing data...

...occur all the time in paleontology ... either because specimens are not complete enough or because their geological age cannot be exactly determined or because specimens are too rare or valuable to use them for a destructive analysis method or because they are for some reason no longer accessible. "N/A" ("not applicable") or empty entries or question marks often symbolize missing data.


Some introductory literature:

Borradaile, G. J. 2003. Statistics of Earth Science Data. Springer, Berlin, 280 pages. ISBN 3540436030

Swan, A. R. H. and M. Sandilands. 1995. Introduction to geological data analysis. Blackwell, Oxford, 446 pages. ISBN 0632032243

Madygen trace fossil paper

Voigt, S. and D. Hoppe. 2010. Mass Occurrence of Penetrative Trace Fossils in Triassic Lake Deposits (Kyrgyzstan, Central Asia). Ichnos 17:1-11. [Link]

Besides the exquisite soft body preservation of insects and tetrapods within some parts of the lacustrine succession, the Triassic Madygen lake shows a rich inventary of invertebrate trace fossils, studied by my colleague from Freiberg Sebastian Voigt.

The interesting point about these ichnofossil assemblages is that they demonstrate a certain differentiation of the lake ground in better and less well aerated zones, displaying different degrees of bioturbation and abundances of indicative ichnotaxa.

You can imagine that fresh water lake grounds only became inhabited stepwise after the conquest of land by animals, so these trace fossil assemblages mark a certain evolutionary level of lake ecosystems, otherwise rarely documented in detail from the Middle to Late Triassic.

Perception of deep time by geologists and biologists

Following the Darwin Year a colloquium lecture by zoologist Prof. Wolfgang Maier from Tübingen dedicated to "Darwin and deep time" discussed Charles Darwin’s role as a geologist who (among others) introduced the concept of deep time (a term later coined for million to several billion year long time ranges in geology) to biology.

Darwin did this by translating a hierarchy of (anatomical) similarity into a tree scheme that linked organisms from successive time slices with thousands of generations separating each two slices (see the scheme from Darwin’s "Origin of Species": [link]). The time slices can be related to certain units of the geological time scale.

Deep time correspondents in stratigraphy …

The problem of imagining time ranges far outside the scale of human experience has been approached by geologists with the method and concepts of stratigraphy: Strata of rock can be interpreted as a succession of time slices. Relative ages and age differences often manifest in an amount of rock which is loosely corresponding to certain a time span if similar rockforming processes are underlying. The relationship between the duration of a process and the amount of materal it creates can be inferred from direct observation of recent systems, allowing the assignment of absolute time (in years or millions of years) to a succession of strata. Given that long-term geological processes are rarely gradual, a more reliable absolute age is provided by radiometric dating.

If you would ask a geologist how he/ she percieves deep time I suppose he/ she would explain that it becomes clear from the slowness of present-day geological processes on the one hand and from the vast amount of products of such processes on the other hand.

… and phylogenetics

The evolution of organisms yields another approximation of deep time: The passing of time manifests in the hierarchical distinctness of living systems. Seeing how slow evolution works in a human being’s life span and how much change in anatomy/ biochemistry etc. must have occurred since last common ancestor of mouse and elephant or of mouse and lemon tree, leads to another way of percieving long time spans.

Regarding a certain distinctness and species richness of a group as a product of a certain number of character changes and speciation events (which is more or less well correlated with time) was probably enhanced by the more quantitative look at phylogenetics since the introduction of cladistics and molecular methods.

When I was attending a workshop on molecular paleobiology in 2008 specialists of that field were using the expression “(addressing) deep time problems” synonymous to phylogenetics of higher systematic groups, i.e. as the study of evolutionary changes that occurred deep down in the tree of animals and other organisms – opposed to let’s say the comparative analysis of human and neanderthal genomes or the radiation of Darwin finches.

The viewpoints of paleontologists…

But how do (present-day) paleontologists percieve deep time? You would expect them to share the view of both, phylogeneticists and stratigraphers, as most of them are taught at least a bit about both fields. However, for a paleontological fieldworker who employs the study of fossils as a means to understand and describe geological processes and paleoenvironmental contexts the flow of time is much easier grasped as a series of events preserved in a succession of rocks (and not as a phylogenetic tree scheme).

On the other hand, as a consequence of the so-called paleobiological revolution, you don’t need to be a field worker to contribute to the understanding of ancient organisms. In fact many aspects of paleobiology require mere laboratory and magazine work and you can spend a lifetime on that without ever considering rocks – naturally the perspective of such a modern paleobiologist on deep time will be strictly that of a phylogeneticist.

…can lead to conflicts?

These different perceptions on deep time and evolution are probably the background why cladistics was (and still is) met with some scepticism by “old school paleontologists” (or by “Eastern Europe school paleontologists”): Instead of considering all kinds of data for phylogenetic hypothesis-making I am supposed to use merely data from the (anatomical, molecular, etc.) comparison of organisms, as if evolution does not manifest in other ways in the geological record.

One could argue that it is possible to integrate other data, i.e. stratigraphic ages and palaeobiogeographical relations, in a cladistic analysis or at least in the discussion of its results, and so assure that hypotheses from the tree perspective on evolution are tested under consideration of independent data.

The idea to use time directly as a character in a parsimony analysis with consecutive time slices as character states may be epistemically unsound, as it is problematic to justify any kind of model assumption how time is weighted with respect to anatomical characters (and implicitly would this mean a post-hoc failure if proximity in time is regarded as indicative for degree of relationship?).

An a posteriori fit to other data – e.g. looking which of the equally parsimonious morphology-only-based time-calibrated trees has shorter lineages of no record (ghost lineages) – might be a better approach, but is still hard to swallow for some people who have problems with parsimony analyses on the basis of (too) small character samples (i.e. with inherent biases due to sample size/ character poorness or ambivalence of fossils).

Madygen News 2009

Expedition. This year's two month expedition to Madygen, Kyrgyzstan, ends in about a week. Rather than merely assembling more fossils the task for 2009 was to carry out further observations concerning the facies architecture and fine stratigraphy of the Madygen Formation - in fact to solve the evolution of the Madygen depositional environment throughout the time comprised by the Triassic sequence of the Madygen SW outcrop area.

Since the ways of communication between Germany and the Kyrgyz outback are difficult I didn't get much of an opportunity yet to talk to Madygen project leader Sebastian Voigt (my de facto chief who is still in the field). But from what I've heard the paleoenvironment is now well explained and some furthergoing approaches, e.g. comparing the conditions of Madygen to those of the other (few) terrestrial lagerstätten of the Triassic, are now feasible.

Symposia contributions and papers

- on the flora:

Moisan, P., H. Kerp, S. Voigt, C. Pott & M. Buchwitz (2009): Cycadophyte foliage from the Triassic Madygen Formation, SW Kyrgyzstan Central Asia. Terra Nova 2009/3:81-82. [Abstract Volume of Annual Meeting of the German Paleontological Society in Bonn] ... the respective paper is soon to come.

- on kazacharthran body and trace fossils: ... still in the review process.

- on fish:

Kogan, I., K. Schönberger, J. Fischer, S. Voigt & M. Buchwitz (2009): A nearly complete Saurichthys specimen from the Triassic of Madygen (Kyrgyzstan, Central Asia). Terra Nova 2009/3: 63-64.

A first note on this find will published at the end of 2009 in Freiberger Forschungshefte.

SVP poster on egg capsules and teeth of hybodont sharks, which have been discovered in 2008: Fischer, J., S. Voigt, M. Buchwitz & J.W. Schneider (2009): The selachian fauna from the non-marine Middle to Late Triassic Madygen Formation (Kyrgyzstan, Middle Asia): preliminary results. JVP 29 (3, suppl.): 95A-96A.

- on chroniosuchians:

Buchwitz, M. & S. Voigt (2009): Locomotion aspects of a chroniosuchid carapace. In: D. Schwarz-Wings, O. Wings & F. Sattler (eds.): 7th Annual Meeting of the European Association of Vertebrate Paleontologis - Abstract Volume. Aachen, 2009, p.14.

Buchwitz, M. & S. Voigt (2009): Phylogenetic and functional implications of the chroniosuchian osteoderm morphology. Terra Nova 2009/3: 25.

I'm trying hard to finish these manuscripts just now. The first description of the new chroniosuchid species, focussing on the skull features, is 'in press'.

- about the thing that must not be named:

Buchwitz, M., S. Voigt & J. Fischer (2009): Dorsal appendages of You-know-what reconsidered: aspects of development and the link to the evolution of filamentous integumentary structures. JVP 29 (3, suppl.): 72A.

...there is another longer manuscript putting some effort into the detailed description/documentation and a discussion of some rather modest model (... but I cannot really tell yet whether an 'accept' is feasible in the near future).

- on the depositional environment of the Lagerstätte Madygen and its tetrapod localities:

Voigt, S., M. Buchwitz, J. Fischer, P. Moisan & I. Kogan (2009): Lagerstätte Madygen - outstanding window to a continental Triassic ecosystem. JVP 29 (3, suppl.): 196A.

Buchwitz, M., S. Voigt, J. Hentschke & P. Moisan (2009): The Triassic Madygen Formation (Kyrgyzstan, Middle Asia) features a new tetrapod locality. Terra Nova 2009/3: 25-26.

...the latter poster introduces some (real) archosaur finds from 2008.

Questionnaire for Geobloggers(incl. Paleobloggers)

http://geoblogs.stratigraphy.net/survey/

The organisator is my former study colleage Lutz Geißler (now M.Sc. in geology), who is at the German forefront of publicising geoscience - with his web portals geoberg.de, geonetzwerk.org, and with his postcard/ poster/ online campaign "Wir sind überall." ("We are everythere!" - referring to the role geoscience plays in daily life/ for the satisfaction of basic needs).

Fieldwork Photo of the Week

Badlands of the SW outcrop area (Urochishche Madygen). Reddish colours mark the "Variegated Member" of the Madygen Formation. In the distance: tree tops of the Madygen river oasis.

Fieldwork Photo of the Week

Colourful Jurassic strata. Who can see the unconformity?

Fieldwork Photo of the Week

Excursion group 2008 and Madygen badlands, close to the boundary between "Variegated Member" (T3) and "Upper Graycolored Member" (T4) of the Madygen Formation (subdivision of Dobruskina 1995).
The transitional zone includes sandstone horizons with large-scale x beds.

Madygen: Recent contributions to symposia

12th International Palynological Congress, Bonn 2008:

Philippe Moisan, Hans Kerp, Sebastian Voigt, Benjamin Bomfleur: The fossil flora of the Madygen Formation from the Middle to Upper Triassic, Kyrgyzstan, Central Asia. Terra Nostra 2008/2: 194

Abstract. The Middle to Late Triassic Madygen Formation (Kyrgyzstan, Central Asia) is a unique fossil lagerstaette for Early Mesozoic insect remains and small reptiles with soft-tissue preservation. Plant fossils from these deposits from are known since the 1930s and constitute one of the richest and most diverse Triassic floras of Eurasia. However, they received very little attention to date and their studies have to date been based on macromorphological features only. We present the first record of epidermal features of this diverse Triassic flora based on recently recovered fossil plant material. Many of the Madygen plant fossils show a highly remarkable preservation. Due to its very fine grain-size, the embedding sediment has often formed a natural cast of the epidermal cell pattern. Such epidermal features allow detailed systematic descriptions as well as palaeoecological interpretations. This fossil flora is dominated by pteridosperms, ginkgophytes, and sphenophytes. In addition, algae, mosses, lycophytes and ferns occur and many are new for this fossil flora. The high abundance of fructifications is of particular interest. Another important aspect of the Madygen flora is that many gymnosperm leaves show evidence for plant-insect interactions (e.g. margin feeding, oviposition, mining traces). The supposed Middle to Late Triassic age of the flora coincides with one of the most important herbivore expansions in the fossil record. However, while this phenomenon has been recognised in the Middle and Upper Triassic of the USA, Western Europe, and South Africa, no data are available from coeval Central Asian sequences. The on-going study aims to provide a revised systematic description of the plants, including epidermal features to characterise the palaeoecosystem of the Madygen lagerstaette in more detail, and to contribute to a better understanding of the evolution of plant-animal interactions during the Early Mesozoic.

Ichnia, Cracow 2008:

Voigt, S., Buchwitz, M.: On the Mermia ichnofacies in a Triassic overfilled lake-basin of Southern Fergana (Kyrgyzstan, Central Asia). Ichnia 2008, Cracow (Poland), September 1- 5

Abstract. Fluvio-lacustrine deposits of the Madygen Formation on the northern rim of the Turkestan Mountains in southwestern Kyrgyzstan are one of the few occurrences of Triassic continental strata in Central Asia. During the 1960s Russian palaeobiologists successfully explored the stratum typicum area of the Madygen Formation for macrofossils, unearthing a remarkably rich Early Mesozoic flora, thousands of insect remains, and unusual reptiles with soft-tissue preservation (Dobruskina, 1995). Considering the number, diversity and preservation of the finds, the locality represents a lagerstaette. Lacking investigations on the geological and palaeoecological background of the findings, however, its particular importance for the evolution of terrestrial ecosystems has not yet been revealed. Thus, a comprehensive approach on the Madygen ecosystem including a detailed facial analysis of the fossil-bearing strata is currently carried out.
The Madygen Formation is an up to 500 m thick series of predominantly siliciclastic rocks, which formed in an intermontane basin under humid to semi-humid climatic conditions. Sedimentary successions are composed of alluvial fan conglomerates, channel sandstones and overbank fines with intercalated coal seams of a highly-vegetated alluvial plain, as well as deltaic sandstones and laminated lacustrine mudstones of basin centre. Shallowing upward sequences and various other features, e.g. dense vegetation, wet soils, and the lack of desiccation cracks, typify the depositional environment of the Madygen Formation as an overfilled lake-basin sensu Bohacs et al. (2000).
Though they were never mentioned in earlier palaeontological reports, trace fossils of the Mermia ichnofacies belong to the most common phenomena of the Madygen fossil assemblage. Networks of tiny, irregularly branched burrows with high bedding-parallel extension are ubiquitous in the laminated mudstones of the lake deposits. Architecture and size of the burrows indicate deposit-feeding, worm-like trace makers such as the extant oligochaetes and aquatic insect larvae. The bioturbation maximum is recorded in mudstones of the transitional sublittoral to profundal lake zone which probably included a chemocline as in some modern stratified lakes. More shallow but clearly submerged parts of the lake were occupied by benthic ostracods and kazacharthra - triopsid-like branchiopods which are thought to be endemic to the Mesozoic of Central Asia (Chen et al., 1996). Body imprints of the kazacharthra occur spatially close to ribbon- and sickle-shaped trace fossils. We are attributing these traces to different types of kazachartran feeding activity: (1) grazing if the ground water layer is well aerated and (2) short-term mud-diving under oxygen-depleted conditions. All ichnia – the shallow penetrative traces and the presumable kazacharthran traces – were produced in the permanently subaquatic environment of a sizeable lake with a minimum length of 1.7 km. The restriction of trace types to a certain ground level relative to the chemocline may yield a basic approach for the subdivision of the Mermia ichnofacies.

German Paleontological Society Meeting, Erlangen 2008:

Voigt, S., Buchwitz, M., Fischer, J., Krause, D.: Longisquama's dorsal skin appendages: new finds from the type locality. Erlanger Geologische Abhandlungen, Sonderband 6: 117

Abstract. During the 1960s Russian palaeobiologists discovered two incomplete diapsid skeletons with skin impressions in lacustrine shales of the Triassic Madygen Formation, a continental sedimentary succession in southwest Kyrgyzstan, Central Asia. Described by A.G. Sharov in 1970 and 1971 the two finds became known for the uniqueness of the species they represent: While Sharovipteryx mirabilis was an early limb-supported reptilian glider with an exceptionally large uropatagium and probably an archosauromorph, Longisquama insignis, whose systematic position is still controversial, displays a series of elongate hockey-stick-shaped skin projections, rooting along the dorsal midline of the body. The appendages are structurally complex and some morphological features, e.g. the presence of a middle axis and the assumed branching, have motivated their comparison with avian feathers. Apart from four Longisquama paratype specimens with isolated skin appendages no further material belonging to one of the two diapsid species has ever been documented.
Here we report three new finds of the Longisquama appendages which have been recovered from the type locality in the northwestern Madygen outcrop area (Urochishche Dzhaylyau-Cho) during fieldwork in 2007: The single exemplar FG 596/V/1 has a length of 28.9 cm, exceeding all other known specimens by at least 100%. Comparable to the appendages of the holotype it comprises a narrow and relatively long proximal section with a tripartite appearance and a relatively short and wide distal section whose two corrugated longitudinal lobes are separated by a prominent middle axis. The apical end and the basal end are not preserved. FG 596/V/2 and FG 596/V/3 represent 3.6 and 3.7 cm long fragments of the distal section. In FG 596/V/1 and FG 596/V/3 the imprints on the left slab and right slab enclose a thin continuous sedimentary core, a feature which has been regarded as indicative for the overall membranous constitution of the appendages.
Especially the very long specimen FG 596/V/1 has some importance for the developmental and functional interpretation of Longisquama’s skin structures: Exceeding the proximal width of other dorsal appendages by only a small amount its length/ basal width ratio is conspicuously high (>50). This can be interpreted as a consequence of uniaxial growth with the constricted proximal and the extended distal section representing two distinct phases of a developmental cycle. Considering the shape and dimensions of FG 596/V/1 we find no easy explanation how the appendages could have formed a closed and stable airfoil, let alone one which produces enough lift to support gliding flight as assumed by the exponents of the hypothesis of a two-wing airborne Longisquama.

Buchwitz, M., Voigt S.: Dermal plates of a Triassic chroniosuchian with unique articulation mechanism. Erlanger Geologische Abhandlungen, Sonderband 6: 24

Fieldwork Photo of the Week

Northern Alay Chain, Batken District, SW Kyrgyzstan.

Standing on massive Devonian limestones we are looking to the NNW. On the right you can see the greenish Madygen river oasis bearing a few farms and fruit plantations. On the left: the badlands represent the SW outcrop area of the Triassic Madygen Formation.

To the north and northwest reddish strata and ribs of Cretaceous conglomerate follow which overlie a narrow stripe of Jurassic. Than there is a succession of mostly Cenozoic rocks forming the core of a syncline.

In the distance you can see larger massifs of mostly Paleozoic schists, limestones and conglomerates. And then there is the greenish plain to the northwest marking another outcrop of fineclastic sediments.

This is Dzhaylyau-Cho ("good meadow"), the NW outcrop area of the Madygen Fm, including "Sharov Quarry" as the most famous locality for insects and tetrapods.


Can you see the artificial band-like wall to the west of the Madygen oasis - this is some relic from ancient times (built under Alexander the Great according to a myth).