56 



J. E. Hede 



are observable at the same locality. As no layers which are everywhere well marked 

 by their fauna or their lithological habitus have been observed, it is impossible 

 to combine the scattered profiles, each of which seldom is much more than 

 20 m. high. 



The greater part of the strata consists of more or less calcareous, grey, soft, 

 thinpaled shales, often approaching sandstones, and rich in small laminae of white 

 mica. In some horizons, however, more or less dense or finegrained limestone is to 

 be found in the form of continuous bands or lenses, sometimes of very large size. 

 The sand-percentage now and then is so rich that real flagstones appear. These 

 often have been called Odarslöv flags. 



Also thickbanked layers destitute of lime (mudstones) sometimes are met with. 



Tullberg thought that the so called »Cardiola shale* or »Colonus shale » was 

 deposited during a transgression: the limestones and the sandstones (i. e. the Öved 

 — Ramsåsa— Bjersjölagård formation) into shallow, but the shales into deeper water. 

 He even thought to have found the shale and the sandstone interstratifying each 

 others at Borstbäcken, near Övedskloster. In 1888 Eichstädt regarded the Colonus 

 shale as a deep-sea formation, but Törnquist immediately after pointed out that 

 the sea in which the deposition of the Colonus beds had taken place was not as 

 deep as that wherein the underlying shales were deposited, and Moberg and Grön- 

 wall have later showed off that the Colonus beds at least partly, might be a de- 

 posit from a rather shallow water. 



In general, the fauna of the Colonus shale is poor as well in species as in 

 individuals, and particularly the shales, disregarding Cardiola interrupta Sow., afford, 

 as a rule only some few graptolites. A great part of the complex is quite barren 

 shales, more exceptionally one may find layers more rich in fossils of several kinds. 

 From all the strata of the many different localities for Colonus shale or Gardiola- 

 bearing shales, we have not to register more than rather above a dozen of grap- 

 tolites, about the same number of crustaceans (ostracods and trilobites), while of the 

 other classes of animals only rare forms are found in them (see the list, pag. 12). 



No more detailed scheme has been worked out. In »Skånes graptoliter» 

 Tullberg states that the lower part is characterized by Monograptus Nilssoni Barr. 

 and Monograptus uncinatus Tullb. which both species are absent in the upper part. 



Under such circumstances, it is obvious that the trials to parallelize the Sea- 

 man Colonus shale with other formations from abroad have not any reliable 

 outcome. A review of several authors' attempts of parallelizing the Colonus shale 

 with the corresponding English Silurians is given in the table, pag. 15. As may 

 bee seen there, the authors have forwarded very different results. We may also 

 find that in later times the common opinion is that the Scanian Colonus shale, 

 upon the whole, has its nearest equivalent in the English Lower Ludlow, and 

 especially is this opinion maintained of authors acquainted with the graptolite faunas. 

 Whether the Aymestry Limestone, too, in this case is to be included in the Lower 

 Ludlow or not, is a matter of question. 



