14 



PALEOZOIC FOSSIL SPORES 



seems to lack haptotypic features, may 

 be generically similar to some of the 

 spore-like rugulose-membranous associ- 

 ates of Tasinanites in American deposits. 

 So far as these plant microfossils and 

 others of similar character but question- 

 able nature aref concerned, an adequate 

 study of them is hardly begun. 



The essential point to be made in 

 regard to ''Sporangites/' which geologists 

 generally consider is well known, is that 

 Dawson applied the name in the first 

 place to ambiguous material and then 

 later applied it without consistency to 

 specimens of at least two other diverse 

 and unrelated types. He further con- 

 fused its application in conjunction with 

 at least two other generic names. Geolo- 

 gists have accepted one of the usages of 

 Dawson, but as this does not correspond 

 with Dawson's original interpretation it 

 seems impossible to retain it in systematic 

 usage. The term "sporangite" ought 

 therefore to be considered no more than 

 a descriptive designation without tax- 

 onomic implication. 



The systemic designation Tasmanites 

 was rejected by Dawson who recognized 

 the similarity of Tasmanites punctatus 

 Newton (1875) to his Sporangites hu- 

 ronensis (Dawson 1886, p. 116) because, 

 as the "name Sporangites had priority, I 

 (i.e., Dawson) do not think it necessary 

 to adopt this term (Tasmanites), although 

 there can be little doubt that these organ- 

 isms are of similar character." This 

 similarity can be verified from Newton's 

 illustrations by any one who has care- 

 fully examined abundant sporangite speci- 

 mens from the Devonian-Mississippian 

 black shale, but the similarity is by no 

 means evident if all the various inade- 

 quate figures of "S. huronensis" given 

 by Dawson and his contemporaries are 

 consulted. 



The best evidence that at least many 

 of Dawson's vS'. huronensis specimens, 

 and particularly those expressly men- 

 tioned by Orton, are similar to those of 

 Newton has been presented in the cred- 

 itably illustrated work by P. F. Reinsch, 

 vol. II of the Micro-Paleophytologia,' 

 published in 1884. Material from the 

 Ohio shale and from Chicago sent by 

 Orton and B. W. Thomas is described 

 and illustrated and comparisons are read- 

 ily made with similar material from 



Newton's tasmanite which Reinsch ob- 

 tained from the British Museum. Reinsch 

 assigned these forms, along with others, 

 in his group called the Discieae, char- 

 acterizing them generally as 



compressed disc-like plant bodies of original 

 subspherical or subelliptical outline. They are 

 entirely closed, with walls sometimes perforate 

 and show a thin central cavity which has been 

 reduced by compression. 



Variations in the walls are mentioned 

 due to inclusion of other forms which 

 seem to resemble Calcisphaera William- 

 son (1880, p. 521), Sporocarpon Wil- 

 liamson (1879, pp. 346-349; 1880, pp. 

 507-11), and many other diverse forms, 

 some of which may even represent true 

 sporangia of articulate plants. Reinsch 

 also described 15 kinds of Discieae from 

 the older Mesozoic. For the most part 

 forms derived from the Carboniferous 

 of central Russia and Saxony contrast 

 sharply with the Tasmanites forms from 

 America, Australia and Tasmania. These 

 last evidently were chiefly in mind as he 

 described the Discieae, for his group 

 description fits them best. Specific no- 

 menclature is applied to only one form 

 so that Reinsch's work, although it shows 

 best the characteristics of various Tas- 

 manites specimens, is essentially not a 

 taxonomic contribution. But since it 

 establishes the similarity of American and 

 Tasmanian forms we may feel no hes- 

 itancy in calling these peculiar bodies 

 Tasm^anites and in accepting Newton's 

 species as the type for the genus. It 

 seems so generally similar to some of 

 the material provided by Orton and 

 Thomas there is a question as to proper 

 specific distinction between them, but 

 being so widely separated geographically 

 as they are, and stratigraphically as they 

 seem to be, the forms should remain under 

 separate names, at least until a definite 

 first-hand study can be made. No spe- 

 cific definitions are attempted here, but it 

 is felt that the generic definition given 

 below is sufficiently accurate to serve to 

 distinguish the group from forms which 

 unmistakably are spores of cryptogams 

 and higher plants, and from several other 

 kinds of problematic fossils which are 

 found in Illinois (and probably else- 

 where) associated with Tasmanites, but 

 which must be considered generically 

 distinct from it. 



