The macrospores collected by Mr. Thomas from the Chicago clays and shales conform closely to those of Kettle Point, and probably belong to the same species. Some of them are thicker in the outer wall, and show the pores much more distinctly. These have been called by Mr. Thomas S. Chicagoensis, and may be regarded as a varietal form. Specimens isolated from the shale and mounted dry, show what seems to have been the hilum or scar of attachment better than those in balsam.
Sections of the Kettle Point shale show, in addition to the macrospores, wider and thinner shreds of vegetable matter, which I am inclined to suppose to be remains of the sporocarps.
2. Protosalvinia (Sporangites) Braziliensis, Dawson, “Canadian Record of Science,” 1883.—Macrospores, round, smooth, a little longer than those of the last species, or about one seventy-fifth of an inch in diameter, enclosed in round, oval, or slightly reniform sporocarps, each containing from four to twenty-four macrospores. Longest diameter of sporocarps three to six millimetres. Structure of wall of sporocarps hexagonal cellular. Some sporocarps show no macrospores, and may possibly contain microspores. The specimens are from the Erian of Brazil. Discovered by Mr. Orville Derby. The formation, according to Mr. Derby, consists of black shales below, about three hundred feet thick, and containing the fucoid known as Spirophyton, and probably decomposed vegetable matter. Above this is chocolate and reddish shale, in which the well-preserved specimens of Protosalvinia occur. These beds are very widely distributed, and abound in Protosalvinia and Spirophyton.
3. Protosalvinia (Sporangites) bilobata, Dawson, “Canadian Record of Science,” 1883.—Sporocarps, oval or reniform, three to six millimetres in diameter, each showing two rounded prominences at the ends, with a depression in the middle, and sometimes a raised neck or isthmus at one side connecting the prominences. Structure of sporocarp cellular. Some of the specimens indicate that each prominence or tubercle contained several macrospores. At first sight it would be easy to mistake these bodies for valves of Beyrichia.
Found in the same formations with the last species, though, in so far as the specimens indicate, not precisely in the same beds. Collected by Mr. Derby.
4. Protosalvinia Clarkei, Dawson, P. bilobata, Clarke, “American Journal of Science.”—Macrospores two-thirds to one millimetre in diameter. One, two, or three contained in each sporocarp, which is cellular. The macrospores have very thick walls with radiating tortuous tubes. Unless this structure is a result of mineral crystallisation, these macrospores must have had very thick walls and must have resembled in structure the thickened cells of stone fruits and of the core of the pear, or the tests of the Silurian and Erian seeds known as Pachytheca, though on a smaller scale.
It is to be observed that bodies similar to these occur in the Boghead earthy bitumen, and have been described by Credner.
I have found similar bodies in the so-called “Stellar coal” of the coal district of Pictou, Nova Scotia, some layers of which are filled with them. They occur in groups or patches, which seem to be enclosed in a smooth and thin membrane or sporocarp. It is quite likely that these bodies are generically distinct from Protosalvinia.
5. Protosalvinia punctata, Newton, “Geological Magazine,” New Series, December 2d, vol. ii.—Mr. Newton has named the discs found in the white coal and Tasmanite, Tasmanites, the species being Tasmanites punctatus, but as my name Sporangites had priority, I do not think it necessary to adopt this term, though there can be little doubt that these organisms are of similar character. The same remark may be made with reference to the bodies described by Huxley and Newton as occurring in the Better-bed coal.
In Witham’s “Internal Structure of Fossil Vegetables,” 1833, Plate XI, are figures of Lancashire cannel which shows Sporangites of the type of those in the Erian shales. Quekett, in his “Report on the Torbane Hill Mineral,” 1854, has very well figured similar structures from the Methel coal and the Lesmahagow cannel coal. These are the earliest publications on the subject known to me; and Quekett, though not understanding the nature of the bodies he observed, holds that they are a usual ingredient in cannel coals.