652 Palaeontologie. 



Montana. It shows an irregulär, cylindrical or tubulär growth. It is 

 difficult to conceive of the tubulär structure of Greysonia as a deposit 

 made by algae, but with the example of the varied forms of recent 

 deposits made by Cyanophyceae and the other fossil forms described 

 in this paper the author is prepared to consider Greysonia as of 

 algal origin. 



Copperia, another new genus, resembles Greysonia. But from 

 the form of the tubes and the irregulär habit of growth the author 

 concluded to give it a distinct generic designation. The Single 

 species, C. tuhiforniis, occurs in the same locality as Greysonia. 



The new genus Collenia comprises several species: C compacta, 

 C. ? frequens (formerly described by the same author as Cryptosoon 

 freqtiens), C. occidentale (Dawson), C. undosa, and an undetermined 

 species. They resemble much to Cryptosoon Hall. Both have a 

 laminated appearance in sections, the concentric lamellae varying 

 in thickness and in the width of their interspaces, but when we 

 compare the mode of growth we find that Collenia has an encrusting 

 like growth that forms a dome-shaped body with the edges of the 

 lamellae pointing downward, while Cryptosoon grows in a cup-shaped 

 form with the edges of the lamellae on the upper surface. 



C. compacta and C? frequens occur in the Siyeh limestone, the 

 first in the Glacial national Park, Montana, the second in the Little 

 Kootna Creek, Chief Mountain quadrangle, xMontana. C. undosa was 

 found in the Beltian series, Spokane Shales, Meagher County, 

 Montana. 



Archaeosoon acadiense Matthew has been described from the 

 „Laurentian" limestone, St. John River, near St. John, New Bruns- 

 wick. Matthew compared it with Eosoon canadense. The present 

 writer is of opinion that it is ot algal origin. 



An interesting new genus is Camasia. By treating the specimen, 

 with hydrochloric acid, chains of microscopic cells could be obtained , 

 which resemble Cyanophyceae. The genus has a compact layer-like 

 growth with numerous irregulär tube-like openings that give a 

 spongoid appearance in cross sections of the tubes. Only one species 

 is described, C. spongiosa, from the Beltian Series, Newland 

 limestone, Meagher County, Montana. It is unusually interesting 

 owing to its resemblance to the deposit made by the Cyanophy- 

 ceae in the fresh-water lakes of New York, Michigan, and 

 elsewhere. 



A remarkable addition to the Algonkian algal flora is the new 

 genus Gallatinia, with G. pertexa, from the Belt terrane, Gallatin 

 County, Montana. The external form is discoid, circular, flattened. 

 The outer ring is united to the center by seven ray like arms 

 arranged in a more or less irregulär manner. The outer border 

 ring is formed of fine, irregulär lamellae, that slope inward more 

 or less from the base to the upper surface. The radiating arms are 

 formed of a series of V-shaped lamellae that extend down into the 

 mass of the specimen a distance equal to about their width at their 

 upper surface. The border ring and arms are connected by a mass 

 of vesicular lamellae that fufl the interior of the specimen. This 

 genus occurs as flattened concretions which the people in the 

 vicinity call fossil turtles. Upon examining these, there was very 

 little to indicate that it was more than an ordinary septaria-like 

 concretion. Cutting a cross section on one side and treating it with 

 acid the wonderful interior and exterior structure was developed. 

 The specimen is formed of a siliceous, bufif weathering material 



