10 



DESCRIPTION OF PLATES. 



[All figures are of natural size. J 



Plate I. 

 Cryptozoon australicum, sp. nov. 

 Fig. 1. A group of columns exposed in strong relief by weather- 

 ing. The laminae are apparently convex to the direction of growth. 

 The middle column, in front, has an expanded base. 



Fig. 2. A group of columns possessing, apparently, concave 

 lamina?. The columns exhibit a regular parallelism of growth 

 without bifurcation. Exposed on weathered surface of limestone. 



Plate II. 

 Cryptozoon australicum, sp. nov 

 Fig. 1. Longitudinal view of weathered column possessing 

 concave and wavy laminae. 



Fig. 2. End view of same specimen showing broken concave 

 laminae. 



Plate III. 



Cryptozoon tessellatum, sp. nov. 



Slab of limestone, about an inch thick, in which the fossils 

 and matrix have weathered equally to a relatively flat surface. 

 The columns are of irregular size and shape, but maintain equal 

 distances from each other. The intercolumnar space is filled with 

 amorphous limestone, which gives the stone a tessellated appear- 

 ance. The opposite face is similar to that shown in the figure, 

 and the vertical sections, on the sides of the stone, show the 

 characteristic lamination of the organism. 



Plate IV. 

 Cryptozoon tessellatum, sp. nov. 

 Fig. 1. A slab rubbed down and polished showing transverse 

 sections of the columns, which are similar to those seen in plate iii. 

 Fig. 2. Polished longitudinal section of a column, with convex 

 laminae, showing increase of diameter by growth. 



Plate V. 

 Cryptozoon proliferum, Hall. 



[This plate has been reproduced by the courtesy of Dr. Walcott r 

 who kindly forwarded his original photographs that they might be 

 used for purposes of comparison in this paper. See Smithsonian 

 Miscell. Colleo. (Cambrian Geology and Palaeontology), vol. lvii., 

 No. 9. plate 37. The "Description of Plate" supplied below is 

 that of Dr. Walcott's.] 



Fig. 1 (natural size). View by transmitted light, of a thin 

 transverse section, showing the lamellae. 



Fig. 2 (natural size). View by transmitted light, of a thin 

 section, showing the lamellae where there was a slight dislocation r 

 caused by irregularity of growth. 



Fig. 3 (natural size). View of the weathered surface of lime- 

 stone, showing several specimens. 



The specimens represented by figs. 1 to 3 are from the Upper 

 Cambrian shaly calcareous sandstone, resting on massive layers of 

 Potsdam sandstone, east side of the town of Whitehall, Washington 

 County, New York 



