Trygław
A label, not a finding
Proper name of the boulder in Tychowo (according to V2: in the cemetery).
West Pomerania · three glacial erratics
A name is not a rock. A rock is not an address.
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Trygław
rock according to the source [2]dark grey paragneiss
regional hypothesis from the literature -
Szwedzki Kamień
rock according to the source [3]granite gneiss
source area not established -
Głaz Omszały
rock according to the source [3]granite
source area not established
The ice sheet carried rocks to Pomerania from the north, but of the three boulders described here, only one has a cautious regional hypothesis in the literature cited. The other two have a rock type and a name, but no address. Below you can check what follows from each feature.
The pebble shapes are conventional, not outlines of the boulders. The page contains no photograph of any of them: there is no photograph of our own for Szwedzki Kamień or Głaz Omszały, and the Wikimedia Commons photograph of Trygław is only a link (source [4]).
What can be inferred from a single feature?
Choose a feature of the boulders. The result shows it for all three boulders at once, marked as recorded in the source, only estimated, or absent from the source cited. Missing information is not zero and not “no”.
- recorded in the source
- hypothesis or estimate from the literature
- absent from the source cited
- a label, not a finding
Proper name
Szwedzki Kamień
A label, not a finding
Traditional name of the boulder in Bukowe Zdroje. It contains the word “szwedzki” (Swedish).
Głaz Omszały
A label, not a finding
Name of the boulder in Szczecin Landscape Park. “Omszały” means covered in moss.
Allows us to say
Which boulder it is and how to find it in registers. A name is a convention among people, not a measurement of the rock.
Says nothing about the journey
Neither what rock the boulder is nor where it came from. The word “szwedzki” in the name does not point to a Swedish locality: in the PIG table this boulder has no region assigned [3]. “Omszały” describes the surface, not the rock.
Rock type (petrographic identification)
Głaz Omszały
Recorded in the source
Granite [3] (table 7, item 23). An igneous rock, a different identification from granite gneiss.
Allows us to say
What rock the boulder is according to the description in the source. Paragneiss, granite gneiss and granite are three different identifications, so the same word “stone” covers different rocks.
Says nothing about the journey
The rock type is not in itself an address: granites and gneisses occur in many regions, so the identification does not point to a locality. Narrowing down the area requires a petrographic analysis of the boulder itself (minerals, texture). There is no such analysis in this material, and the identifications need a petrographic consultation.
Striations and traces of the ice sheet
Trygław
Recorded in the source
Glacial striations; A. Ber links them to the ice sheet of the last glaciation [2].
Szwedzki Kamień
Absent from the source cited
Listed as a glacial erratic; the table does not describe striations [3].
Głaz Omszały
Absent from the source cited
Listed as a glacial erratic; the table does not describe striations [3].
Allows us to say
That the surface of the boulder bears traces of abrasion by moving ice. This ties the boulder to the general transport mechanism (three stages below).
Says nothing about the journey
Where the boulder was broken off, which way the ice flowed, or how many times it changed direction. The absence of any mention of striations on the other two boulders does not mean they have none: it is missing data, not zero.
Source area in Scandinavia
Trygław
Hypothesis from the literature
The area around Vidbo or Uppsala in Sweden as probable (“probably”) [2].
Szwedzki Kamień
Absent from the source cited
Area not established: the table gives no region [3]. We draw nothing for it.
Głaz Omszały
Absent from the source cited
Area not established: the table gives no region [3]. We draw nothing for it.
Allows us to say
For Trygław: that the literature points to the area around Vidbo or Uppsala in Sweden as probable. This is a direction to check, not a result that can be reproduced from the look of the boulder alone.
Says nothing about the journey
It does not define a route, a single locality or a percentage of certainty. The source gives no certainty figure, so the page does not invent one. For the other two boulders there is nothing to mark: an empty outline of “the whole of Scandinavia” would look like an answer, and it is not one.
Relationship diagram for Trygław, not a map. No scale, no coordinates, no coastline.
- Hypothesis region: the area around Vidbo or Uppsala, according to A. Ber, with the word “probably” [2]. The hatching and dashed outline mark a hypothesis.
- The Baltic Sea, shown conventionally as a band.
- Tychowo, the location of the boulder.
There is no line between A and C. This is deliberate: the source gives a probable region, not the course of a route, and the ice sheet changed direction in successive phases of the glaciation. There is no counterpart of this diagram for Szwedzki Kamień and Głaz Omszały, because the source cited does not narrow down the area.
Size (volume)
Trygław
Estimate from the literature
Approx. 700 m³ according to A. Ber [2]. This is an estimate, not a modern scan. V2 also described Trygław as the largest glacial erratic in Poland: to be checked in the source.
Allows us to say
How large the boulder is according to the literature (for Trygław), and what is known and what is not. The mass calculator from V2 has been removed, because for two of the three boulders there are no dimensions to enter (changes since V2).
Says nothing about the journey
Size is not evidence of origin or of the length of the journey. The lack of dimensions for two boulders is not zero and does not mean a “small boulder”.
All features at once
| Feature | Trygław | Szwedzki Kamień | Głaz Omszały |
|---|---|---|---|
| Proper name | a label, not a finding | a label (the word “szwedzki” is not evidence) | a label, not a finding |
| Rock type | dark grey paragneiss | granite gneiss | granite |
| Striations and traces of ice | glacial striations | no description of striations in the table | no description of striations in the table |
| Source area | hypothesis: the area around Vidbo or Uppsala | not established, no region in the table | not established, no region in the table |
| Size | approx. 700 m³ (estimate) | no dimensions in the table | no dimensions in the table |
Three sentences you may write, and four you may not
A description of a boulder for a note or a photo caption. The left column keeps to the material; the right one contains over-interpretations that are easy to slip in.
Follows from the material
- Trygław: dark grey paragneiss; according to A. Ber (1999) probably from the area around Vidbo or Uppsala (“probably”).
- Szwedzki Kamień: granite gneiss, listed as a glacial erratic; source area not established.
- Głaz Omszały: granite, listed as a glacial erratic; source area not established.
Does not follow from the material
- “Szwedzki Kamień comes from Sweden, because that is its name.”A name is not an analysis of the rock.
- “Trygław travelled from Uppsala to Tychowo.”The source gives a probable region, not a route.
- “Trygław comes from Vidbo with 90 per cent certainty.”The source gives no percentage at all.
- “Głaz Omszały has no glacial striations.”No mention in the table means no data, not an observed absence.
How a boulder could have got here and how to look at it
Three stages of the general mechanism [1]
- Pick-up. Moving ice pulls blocks off the bedrock.
- Transport. The ice carries the material, and on the way it can abrade rock and leave polished surfaces and striations.
- Deposition. When the ice disappears, boulders and sediments are left behind: tills, sands and gravels.
This is a general description. The route of none of the three boulders can be read from it alone.
In the field
- Do not chip off samples, scratch the surface or scrape off lichens: striations and polished surfaces are easily destroyed.
- According to V2, Trygław stands in the cemetery in Tychowo. Respect the solemnity of the place and do not climb on the boulder or under the cross.
- According to V2, Szwedzki Kamień and Głaz Omszały lie in Szczecin Landscape Park “Puszcza Bukowa” (Beech Forest). Keep to the marked trails and the park rules.
- Check the current legal protection status, location and access with the land manager. This page has not verified them.
What has changed since V2
- The ellipsoid mass calculator has been removed (V ≈ π/6 · L · W · H). The only figure in the material is the approx. 700 m³ from the literature for Trygław, and the calculator merely recalculated the assumptions entered and said nothing about origin. Size remains as one of five features.
- The checklist with drop-down lists has been replaced by a choice of feature. The checklist worked like a “has an address / has no address” machine. Now you can see what each feature says about the three boulders at once. Its conclusions are kept: a name is not evidence, striations are not an address, a rock type is not an address.
- The notes register in localStorage has been removed. The page saves nothing in the browser.
- The map with “the whole crystalline shield” has been removed for boulders without a region, along with the “texture” diagrams of rocks without a photograph: they looked like a mineralogical result or proof, and they were neither.
- The photograph loaded from the internet has been removed. The page works offline; the photograph is a link.
- Kept: the data on the three boulders, the caution of the hypothesis (“probably”), the three stages of transport, the field rules and the three PIG sources.
Compare: Version V2 · Version V1 · Atlas catalogue
Sources and limits
The descriptions below come from material taken over from V2. The links are kept, but in this version they were not reopened or checked again.
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Jerzy Gągol, PIG-PIB, Skąd się wzięły głazy narzutowe? [Where did glacial erratics come from?] The general mechanism of pick-up, transport and sedimentation of glacial deposits.
PIG article -
Andrzej Ber, Preliminary list of the Quaternary geosites in Poland, Polish Geological Institute Special Papers, 2 (1999), p. 79. According to V2: the description of Trygław as dark grey paragneiss, an estimate of approx. 700 m³, glacial striations and a cautious hypothesis of the area around Vidbo or Uppsala (“probably”).
PIG document, p. 79 -
Państwowy Instytut Geologiczny, Objaśnienia do Mapy geośrodowiskowej Polski 1:50 000, arkusz Szczecin (228) [Explanatory notes to the Geo-environmental Map of Poland 1:50,000, Szczecin sheet (228)], Warszawa 2005, table 7: monuments of inanimate nature. According to V2: item 22 Szwedzki Kamień (granite gneiss), item 23 Głaz Omszały (granite); the table does not give a source area.
PIG Szczecin sheet -
Photograph of Trygław in Tychowo, Wikimedia Commons, author Brogaj, licence CC0 1.0 according to V2. The page does not display it; the rights status and current description are to be checked at the source.
Open the photograph (external Commons service)
Unverified
- The content of sources [1]–[4] and the page numbers: taken over from V2, not read again. The claim “the largest glacial erratic in Poland” and the value of 700 m³ need to be checked in [2].
- Place names (Tychowo, Bukowe Zdroje, Szczecin Landscape Park “Puszcza Bukowa”) and the fact that Trygław stands in a cemetery: from V2, to be checked. V2 also called the park “Knieja Bukowa”.
- The rock identifications are descriptions from publications, not inspections. A petrographic consultation is needed. “Omszały” and “szwedzki” in the names are explained only linguistically.
- Legal protection, location and access to the boulders: not checked.
- The diagram in the source area section is an illustration of a relationship, without scale and without geometry. The “towards the north” direction is an approximation.