. Carnegie Institution of Washington publication. . FIG. 33. A and B. Two coprolites showing trace of the spiral valve. X 1. C and D. Two coprolites showing the longitudinal ridges. XI. E. Figure of a tooth of an unknown form, No. 7506, U. of Mich. XI- of the Dipnoan fish of the region, but in the light of the great number of the coprolites it is strange that not more of the skeleton of the fish has been found; only two teeth and no other parts of the skeleton have been The third type of coprolite is very different from the other two. These range from to 7 cm. in length. They are a
. Carnegie Institution of Washington publication. . FIG. 33. A and B. Two coprolites showing trace of the spiral valve. X 1. C and D. Two coprolites showing the longitudinal ridges. XI. E. Figure of a tooth of an unknown form, No. 7506, U. of Mich. XI- of the Dipnoan fish of the region, but in the light of the great number of the coprolites it is strange that not more of the skeleton of the fish has been found; only two teeth and no other parts of the skeleton have been The third type of coprolite is very different from the other two. These range from to 7 cm. in length. They are all somewhat curved, sometimes approaching a cres- centic form. In many, especially of the smaller coprolites of this type, the outer side of the curve is marked by deep and regular grooves very evenly spaced (fig. 33 c). This is so striking that when the first fragment of one was found it was suspected that it represented the surface of a Cephalopod shell. In most of the larger coprolites of this type the markings are very obscure or wanting, but the curved form is always character- istic. In the larger forms there is frequently an additional part of the coprolite which fits over the end as a cap or cloak (fig. 33 D). It is impossible to associate this type of coprolite with any definite group of animals; the only suggestion that can be made is that in many amphibians the distal portion of the rectum is thrown into parallel lineal- folds—just such an arrangement as would make linear markings upon the fcecal mass. SEDIS. A small fragment of a jaw contains a very singularly shaped tooth which the author has been unable to identify, or even to determine its relationships. As shown in figure 33 E, the tooth is elongate oval in section, with the greatest diameter parallel to the length of the jaw. In general outline it is reminiscent of the teeth of the Permo- Carboniferous reptile Diadecles, but the upper edge is contracted, slightly concave antero- posteriorly, and has
Size: 1718px × 1454px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorcarnegie, bookcentury1900, bookdecade1900, bookyear1902
