74 Cincinnati Society of Natural History. 



Of these six, five were placed by Brongniart in his sub- 

 genus GiGARTiNiTES. The)' have been generally referred to 

 the genus Chondrites, of Sternberg. There is ever^- reason 

 for believing that this genus, like Fucoides, contains a number 

 of diverse forms, and will have to be finally broken up. 

 Undoubtedly a great number of the species are remains of 

 plants, but those in the li.st above given are doubtless worm 

 burrows. They are, at all events, very problematic organ- 

 isms, and we propose that the genus Gigartinites, Brongniart's 

 section, be establi.shed for the first five species. The 

 species targionii, as the first one described by Brongniart 

 under his section, should be taken as the type. They would 

 then stand as follows : 



Gigartinites targionii, (Br.) Gigartinites furc^tus, (Br.) 

 difformis, (Br.) antiquus, (Br.) 



recurvus, (Br.) 



The figures which are given illustrate these species. They 

 are taken from Brongniart's Histoire des Vegetaux Fossiles, 

 Vol. I. (PI. Ill, Fig. I ; PI. IV, PI. V.) 



The last species of the list is F. circinatiis, and of this we 

 also give a figure (PI. Ill, Fig. 3). It differs in many w'ays 

 from the others, and of it Brongniart says: "This Fuais 

 attained nearly a foot in height; it is in general enclosed in 

 the freestone perpendicularly to and not parallel with the beds, 

 like the most of the plants transported and deposited in the 

 place where the rock enclosing them was formed." (p. 84.) 

 From this statement it seems evident that the fossil was not a 

 plant, and in all probability it represents the remains of a 

 worm burrow. It presents a great analogy to several species 

 described by Billings as Licrophycus. It will be referred to 

 at another time in more detail. 



In 1831 Germar and Kaulfuss'-i" described and illu.strated 

 Fucoides acutus. This is, in all probability, a plant, and is now 

 known under the name of Aphlebia acuta (G. & K.,) Presl. 

 In the .same year (1831) Richard Harlan dcscribedt and illus- 

 trated /''ucoides alleghaniensis as a new species occurring in 

 one of the ridges of the Alleghany Mountains. This species 

 is now generally known as Arthrophycus harlani, but its 



*Acta Acad. Cxs.-Leop. Carol. Nat. Cur., vol. xv, pt. 2, p. 230. 

 tlour Ac.nd. Xat. Sci. Phil., vol. vi, pp. 289-291, pi. i. 



