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Figure 4.8: Widmanstatten Structure of the Gibeon meteorite formed by alternating parallel crystal bands that are arranged in a triangular pattern. Width of rock illustrated 4 cm.

amounts of Carbon, Sulfur, Chromium and Copper, and traces of Zinc, Gallium, Germanium and Iridium.

Between 1911 and 1913, Dr. Paul Range [for whom Rangea is named], state geologist for the German South West Africa government, collected 37 fragments. Several specimens have been donated to research institutions all over the world and 33, with masses ranging from 175 kilograms to 555 kilograms, remain in Windhoek today.

National Monuments Council

August 12, 1993: Having left Africa and returned to Germany, Seilacher and I are meeting with Prof. Hans D. Pflug at his home in Lich, Germany.

Pflug is a pleasant and soft-spoken man. He welcomed me warmly into his home, said he was very pleased to meet me, and handed me a copy of an article I had written that had been translated into German.50 Pflug's mind is abroil with scientific hypotheses, many of them unortho dox. In one of his recent articles he argues that differences in the early earth's gravitational field prevented animals from reaching large size in the past.51 To say the least, this hypothesis will be met with skepticism by most other scientists.

Also a veteran of World War II, Pflug served in the German navy on the battleship Tirpitz. Pflug was wounded during a short post-Navy career as an infantryman. He showed me both snapshots of the Tirpitz and the scars where a Russian bullet had entered near his wrist, passed through his forearm, and exited near his elbow. Only a flesh wound.

Displayed before us was Pflug's entire collection of Namibian Edi-acaran fossils. I wouldn't have thought it possible, but the diversity of form and preservation dwarfed anything in Erni's shed. Pflug was originally trained as a paleobotanist, and this may explain why he, in the 1960s, made some unusually important observations regarding the Nama fossils.

Seilacher began by reminding me that Professor Pflug was the first person not to use the Glaessnerian shoehorning, in other words, the shoehorning of Ediacaran taxa into modern taxa such as the phyla Cnidaria or Arthropoda. Seilacher graciously acknowledged that he had learned this first from Pflug, and that Pflug had made the extremely important observation that Ediacarans represented a completely different lineage, and were perhaps even prokaryotic.

Later discussion turned to the specimen of Rangea shown in figure 4.9. Seilacher asked Pflug whether we could discuss preservation of the fossils, considering the uncertainties surrounding this issue. Pflug asked which aspects of preservation he would like to discuss. Seilacher said that he wanted to learn more about the preservational conditions. It was clear to Seilacher, from his observations of the fossil localities in Australia and Siberia, that the preservational agent was smothering, obrution,52 or "Verschuettung,"53 and that in these deposi-tional environments the most likely cause of such burial was storms. Storm sedimentation covered the fossils and preserved them as a relief on the bedding plane—"Pompeii in a storm sense."

At Mistaken Point in Newfoundland, Seilacher saw the same sort of thing. He had counted 15 different stratigraphic horizons in which the smothering had been accomplished by volcanic ash. Each horizon is a layer of graded tephra or volcanic ash particles. The lowermost layer is prominent as a white band, and it is at the base of this white band that the fossils are preserved. As in Pompeii, the fossils were smothered exactly in living position. They were covered by volcanic ash, and the only generations of organisms to preserve as fossils were those that were alive on each of the 15 successive "Pompeii days." Other generations were certainly present but are not represented by fossils in the intervening strata. The fossils can preserve only at the interface between the upper, muddier phase of the lower ash layer (on which the organisms were living) and the newer, falling ash that snuffed out the community.

Figure 4.9: Rangea schneiderhoehni from Namibia, specimen in the collection of H. D. Pflug. Shown are four subfronds converging at the tip of the composite frond. Scale bar in centimeters.

Figure 4.9: Rangea schneiderhoehni from Namibia, specimen in the collection of H. D. Pflug. Shown are four subfronds converging at the tip of the composite frond. Scale bar in centimeters.

I added that this was similar to the way in which fossils preserve at the base of a turbidite layer. Exactly so, Seilacher replied. He noted that there is an important difference between the fossils in Newfoundland and Australia. Fossil relief is opposite in the two localities. In Australia the fossils are in negative relief on the base of the smothering bed; in Newfoundland they are in positive relief on the top of the smothered bed.

Later discussion turned to "deformed" specimens of Pteridinium in the Pflug collection. Seilacher noted a specimen of Pteridinium that, in his view, grew upward, turned around, and changed polarity (what had been the underside of the "bathtubs" became the insides of the "bathtubs"). Seilacher insisted that this indicated that the ventral and dorsal sides of the organism have no significance in the ordinary, animalian sense. What was ventral here becomes dorsal there. I added that this was the firmest proof we have ever had that Pteridinium is not an animal. Seilacher asked Pflug whether Hans would be allowed to make a cast of this specimen.

In later discussion, Seilacher mentioned to Pflug and me that in the Namibian discussion, Runnegar and Seilacher had come close to agreement on a number of points. In particular, Runnegar seemed to agree that forms such as Pteridinium did not fit any known metazoan body plan, and could be neither ancestral to nor related to any modern body plans. Pflug agreed with this. Seilacher hastened to add, however, that the taxonomic placement of Spriggina and Dickinsonia were not agreed upon in Aus. Runnegar felt that these forms were unrelated to Pteridinium, and that their resemblances were superficial, a consequence of convergent evolution resulting from shared evolutionary responses to a unique moment of Earth history.

The hard-won silicon and its shape form remained in Germany for some time for casting at Tübingen, but Seilacher eventually brought it with him to Yale University. There his technician made three casts, one in plaster and two in fiberglass. The fiberglass casts were painted an even tan color to approximate the color of the Nama sandstones. I received one of the fiberglass casts and carried it in a geology van back to Mount Holyoke College. The cast was a marvelous creation and, in my possession, immediately led to long-lasting study sessions with my paleontology students.

In fall of 1993 I had the honor of presenting Dolf with the Medal of the Paleontological Society. On ascending the platform to receive the award, he fell off the podium, but fortunately was not seriously injured. I mentioned the slab in my citation for him, noting that it was "arguably the best contiguous slab of Ediacaran fossils in the world." When my citation for Seilacher was published in July 1994, it apparently caught the attention of prominent paleontologists.54

In mid-August I received a telephone call from the office of Stephen Jay Gould at Harvard University, asking whether I would provide an illustration of the slab for an article he was writing for Scientific American. I agreed to do this and asked for someone to contact me with more details.55 A good deal later I was contacted by Michelle Press at Scientific American with a second request to do a photograph for them. She said she wanted a color photograph, and that she wanted it within the next couple of days. Regarding the photograph's quality, she said, "It has to be stunning."

This posed a problem for me, as my copy of the slab was not properly prepared for the making of a stunning photograph. The tan paint on the surface was attractive but lacked sufficient contrast. I needed some way to boost the contrast of the specimen and I needed it done quickly.

I raced home to my house and found a small can of dark wood stain and a brush. Going back to campus, I tested the stain on a hidden part of the slab and test results were encouraging. So I painted the entire slab with a thin coat of wood stain.

The process worked well. When finished I had a slab with sufficient contrast. It looked like "natural" rock but was much more attractive than the original surface of casted rock surface had ever been. I carried the slab cast three floors downstairs from my office to the back of Clapp Laboratory and set it up outside because I felt that natural lighting would be best for the photograph. Rain was threatening but the diffuse light through heavy clouds seemed to provide the lighting I required. I shot an entire roll of color film, and raced into Springfield, Massachusetts, for one-hour developing.

Results were pleasing (color plate 12). Michelle Press said that the photos were indeed stunning and looked three-dimensional, and said, "We are very grateful to your for your heroic efforts on our behalf." The result, which appeared as a full-page illustration to lead off Gould's article, appeared in the October 1994 special issue of Scientific American titled "Life in the Universe."

Seilacher seemed quite pleased at this accomplishment, only the first of what I anticipate will be many more fortunate results of his eclectic expedition to Namibia.

Notes

1. J. K. Wright, "Foreword," in C. H. Hapgood, Maps of the Ancient Sea Kings, pp. ix-x (Philadelphia: Chilton Books, 1966).

2. The name Seilacher is derived from Ache, ancient German for "river," and Seil, meaning "rope," although the latter may be a corruption (A. Fischer, written communication, 1996). Thus the name may mean "meandering river." Seilacher himself puns that the name is akin to selachians, the sharks.

3. See p. 325 in A. Seilacher, "Divaricate Patterns in Pelecypod Shells," Lethaia 5 (1972):325-343.

4. Incidentally, this is where Seilacher celebrated his official retirement on October 1, 1990, at 0.00 hours.

5. A large body of granitic rock, formed by cooling lava below the earth's surface.

6. Eldridge M. Moores, personal communication, March 2, 1997. Moores spent most of a week with Martin doing field work in the vicinity of the Orange River, Namibia.

7. Lithops seeds can be purchased for $3.99 from Thompson & Morgan Inc., Dept. RT, Jackson, New Jersey 08527. Ask for "Living Stones," Lithops, 2546 Greenhouse Perennial, net weight 4 mg. The instructions state that "no water should be given at all throughout the winter and early spring."

8. J. D. Ward and I. Corbett, "Towards an Age for the Namib," in M. K. Seely, ed., Namib Ecology: 25 Years of Namib Research, pp. 17-26 (Pretoria, South Africa: Transvaal Museum, 1990).

9. Pronounced VIND-hook.

10. E. M. Thomas, The Harmless People (New York: Knopf, 1959).

11. R. M. Miller, "A Note on Three Unusual Sedimentary Structures in

Sandstone of the Auborus Formation, South West Africa," Journal of Sedimentary Petrology 45, no. 1 (1975): 113—114; see also A. Seilacher, Fossile Kunst: Albumblätter der Erdgeschichte (Korb, Germany: Goldschneck-Verlag, 1995).

12. Dacque served as Heinz Lowenstam's doctoral adviser.

13. See p. 28 in P A. Munz, California Desert Wildflowers (Berkeley: University of California Press, 1962).

14. See p. 13 in R. Williams, The Non-Designer's Design Book (Berkeley, California: Peachpit Press, 1994).

15. An unconformity is a level in a sequence of layered rocks where there was a significant break in the deposition of sediments. If the rocks below this level have been tilted and eroded, it is called an angular unconformity.

16. J. H. Wellington, South West Africa and Its Human Issues (Oxford: Clarendon Press, 1967).

17. A. J. Tankard, M. P A. Jackson, K. A. Eriksson, D. K. Hobday, D. R. Hunter, and W. E. L. Minter, Crustal Evolution of Southern Africa (New York: Springer Verlag, 1982); G. J. B. Germs, "Implications of a Sedimentary Facies and Depositional Environmental Analysis of the Nama Group in South West Africa/Namibia," Special Publications of the Geological Society of South Africa 11 (1983):89—114.

18. Which, according to Seilacher, all have their convex sides down. This would have been an unstable position had they been transported.

19. Indicative of Dutch culinary influence.

20. Float specimens are rocks that have been broken off of, but have not traveled far from, their bedrock source.

21. Seilacher has interpreted Protolyellia as both a psammocoral (A. Seilacher and R. Goldring, "Class Psammocorallia (Coelenterata, Vendian-Ordovician): Recognition, Systematics, and Distribution," Geologiska Föreningens i Stockholm Förhandlingar 118 [1996]:207—216) and as probable microbial sand balls (written communication, March 3, 1997).

22. These men belonged to the !Xam people of the San (Bushman) language group. The ! refers to the click sound of this language.

23. W. H. I. Bleek, L. C. Lloyd, and G. M. Theal, Specimens of Bushman Folklore (London: George Allen, 1911).

24. A. Solomon, "Rock Art in Southern Africa," Scientific American 275 (1996):106-113.

25. I. Tattersall, The Last Neanderthal (New York: Macmillan, 1995).

26. Anonymous, "Namibia's Ancient Big Bird," Science 263 (1994):176.

27. Thrombolites are stromatolite-like structures lacking the distinctive internal laminations or layering.

28. Brain now says that he has found fossils in these cherts.

29. H. D. Pflug, "Neue Fossilreste aus den Nama-Schichten in SüdwestAfrika," Paläontologische Zeitschrift40 (1966):14-25.

30. J. W. Valentine, "Dickinsonia as a Polypoid Organism," Paleobiology 18 (1992):378-382.

31. The tube worm fossils associated with Ediacarans in Australia; see B. Runnegar, "Proterozoic Eukaryotes: Evidence from Biology and Geology," in

S. Bengtson, ed., Early Life on Earth, pp. 287-297 (New York: Columbia University Press, 1994).

32. Easternmost locality (G) in Pflug's Ernietta paper; H. D. Pflug, "Neue Fossilreste aus den Nama-Schichten in Südwest-Afrika," Paläontologische Zeitschrift 40 (1966):l4-25.

33. What Seilacher called "Flädle" structure (after a Swabian pasta dish) in the Kliphoek member of the Nama is what is commonly known as "dish structure," formed by intrastratal dewatering within a mature and well-sorted bed of sand (Frieder Pflüger, personal communication, September 13, 1996).

34. G. R. McLachan, "Taxonomy of Agama hispida (Sauria: Agamidae) in Southern Africa," Cimbebasia, Series A, 5, no. 6 (1981):219-227.

35. See p. 147 in R. J. F. Jenkins, "Functional and Ecological Aspects of Ediacaran Assemblages," in J. H. Lipps and P W. Signor, eds., Origin and Early Evolution ofthe Metazoa, pp. 131-176 (New York: Plenum, 1992).

36. M. McMenamin, "Burros," The Stanford Daily 171, no. 41 (1977):2; S. Stueckle, "Mustang Savvy," Hemispheres (June 1994):80-89.

37. New York: Random House, 1990.

38. J. H. Wellington, South West Africa and Its Human Issues (Oxford: Clarendon Press, 1967).

39. M. McMenamin, Carthaginian Cartography: A Stylized Exergue Map (South Hadley, Mass.: Meanma Press, 1996).

40. J. S. Malan, "Social Evolution Among the Ovambo," Cimbebasia, Series B, 2 (1978):12.

41. In an early (and, as it turned out, incorrect) application of continental drift theory, Merensky hypothesized that the Namibian diamonds were a result of the release of deep-seated (and thus diamond-bearing) lavas, erupted along the rift canyon separating South America from western Africa. In fact, the diamonds derived from inland kimberlite deposits are not directly associated with continental breakup.

42. A rock type of explosive volcanic origin with a heterogenous fine-grained matrix; often contains diamonds.

43. R. M. Miller, Namibia Geological Map, 1:1,000,000 (Windhoek: Geological Survey of Namibia, 1990).

44. D. D. Swinbanks, "Paleodictyon: The Traces of Infaunal Xenophyophores?" Science 218 (1982):47-49; L. A. Levin, "Paleoecology and Ecology of Xenophyophores," Palaios 9 (1994):32-41.

45. M. R. Rampino, "Tillites, Diamictites, and Ballistic Ejecta of Large Impacts," Journal ofGeology 102 (1994):439-456.

46. J. D. Ward and I. Corbett, "Towards an Age for the Namib," in M. K. Seely, ed., Namib Ecology: 25 Years of Namib Research, pp. 17-26 (Pretoria: Transvaal Museum, 1990).

47. I'd like to see someone publish a picture book, a photographic essay of all the world's great angular unconformities.

48. See p. 20 in N. Mossolow, Hansheinrich von Wolf und SchloßDuwisib [Hansheinrich von Wolf and Duwisib Castle] (Swakopmund, Namibia: Society for Scientific Development, 1992).

49. A. du Toit, Our Wandering Continents (Edinburgh: Oliver and Boyd, 1937).

50. M. A. S. McMenamin, "Das Erscheinen der Tierwelt," in H. D. Pflug, ed., Fossilien: Bilder frühen Lebens, pp. 56—64 (Heidelberg: Spektrum-der-Wissenschaft-Verlagsgesellschaft, 1989). This book is sold with a separate geological time scale insert meant to be used as a bookmark—splendid idea!

51. H. D. Pflug, "Role of Size Increase in Precambrian Organismic Evolution," Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen 193, no. 2 (1994): 245-286.

52. From Latin obruere, which means "to uproot or excavate."

53. A term commonly used in conjunction with snow avalanches in the Alps smothering a group of skiers (F. Pflüger, personal communication).

54. M. A. S. McMenamin, "Presentation of Paleontological Society Medal to Adolf Seilacher," Journal of Paleontology 68 (1994):916-917.

55. I had done work before for this magazine; M. A. S. McMenamin, "The Emergence of Animals," Scientific American 255 (1987):94-102.

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