Fossils of the Hamilton Group, All 



Fig. 15 Cystiphrjllum Americanum, (Edwards & Haime.) 

 Fig. 15 Cystiphyllum Americanum. " Coral elongated, cylin- 

 dro-turbinate, straio-ht or sli'^-btlv curved, covered by a thin 

 epitheca, and presenting folds of growth more or less marked. 

 When the epitheca is removed, the stride of very thin ribs may be 

 observed. These are equal in size, and straight. The cup is cir- 

 cular, margins thin, excavated ; septal rays distinct and prolonged 

 to the centre under the form of fine striae ; about one hundred may 

 be counted. A verticle section shews a tissue entirely vesicular 

 but which is very dense in the external parts of the fossil ; the 

 vesicles occupying the outside are in general small and oblique 

 sloping inwards and downwards ; those in the centre are larger, a 

 little unequal, and almost horizontal, broader than high, the largest 

 are three millemetres (about one eighth of an inch) in length and 

 1 or 1^ millemetres in heighth ; the small ones are only about 

 one millemetre in breadth." 



This species is the C. cylindrkum of the New ?ork reports. It 

 occurs abundantly in the Hamilton Group in Western Canada. 

 The star shaped mark near the centre of the figure is the base or 

 root of a small encrinite which had attached itself to the specimeu 

 figured by Prof. Hall after the death of the coral. 



The generic name'is derived from the Greek kicstis, a vesicle, or 

 small cavity. Fossils of this genus when cut and polished, or 

 when their internal arrangement is otherwise exposed, do not ex- 

 hibit the reofularlv radiated structure of Streptelasma^ but consist 

 altogether of vesicular structure. This species is usually four 

 inches or less in lenoih and 1 or H in diameter. 



