| 41. | Progress below ground was slow, as a band of hard chert was encountered.
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| 42. | Mount Independence chert was traded across the Northeast.
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| 43. | Rock fragments in this are shales and cherts.
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| 44. | The m�lange was underplated beneath the chert layer.
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| 45. | In 1981, a neolithic axe-head made from greensand chert was found.
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| 46. | The red rock member is hematite stained chert.
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| 47. | The rocks of this sinkhole consist of Dartry Limestone, Knockmore Limestone and chert.
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| 48. | The species was first described from a series of isolated fossil seeds in chert.
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| 49. | The dank walls are shot through with green chert, a rock that Hiroaki covets.
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| 50. | Among petrologists, chalcedony is sometimes considered separately from chert due to its fibrous structure.
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