Benson. — Mazo carp on or the Structural Sigillariostrobus . 58.1 
followed up by a thorough examination of the blocks from which Mazo- 
carpon had been obtained. Striking association with denuded cone-axes 
and with the bark of Sigillaria mamillaris was found. 1 
More reliable evidence was next obtained by a comparison of the 
structural material with the incrustation fossils already admitted to be 
Sigillariostrobus . The history of our slowly accumulated knowledge of the 
cones of Sigillaria has been related by Zeiller 2 and Kidston. 3 Golden- 
berg 4 had previously published diagnoses of Sigillarian cones. Kidston’s 
material, collected by Mr. Hemingway from the Middle Coal Measure 
Strata of Yorkshire, included for the first time a portion of the cone with 
sporangia giving some indication of the form, number, and distribution of 
the megaspores in a species he named Sigillariostrobus ciliaius . 5 Another 
cone of Lower Coal Measure age with larger sporangia was regarded by 
Dr. Kidston as bearing microsporangia. The features of resemblance 
shown by Mazocarpon with these specimens are very numerous and will be 
dealt with in the next section (Section XI). 
Incrustations of complete cones were also figured in natural size and 
cone-axes from which the cone-^scales had fallen. 
Mr. Hemingway was able to provide further specimens of these 
denuded cone-axes (R. H, C. Bot. Museum 2,95), so that material has been 
available for comparison with surface sections of the Mazocarpon cone-axis, 
and it is found that the scars on each are similar in form and size (set 
Fig. 19). 
Dr. Kidston says (loc. cit, p* 51): ‘The shedding of the bracts at 
maturity seems to be a characteristic of Sigillarian cones and one of the 
distinguishing points between them and Lepidostrobusl This tendency to 
fall to pieces is one of the causes in the delay in the interpretation of Mazo¬ 
carpon , but is now shown to be one of the strongest proofs of its Sigillarian 
nature. 
SECTION XI. Detailed comparison of the Structural Material of Mazo¬ 
carpon zvith the Incrustation Remains of Sigillariostrobus. 
1. The Meg asp orange. 
If one compares Fig. 18, which is a single radial section of a mega- 
sporange of Mazocarpon , or, still better, Text-fig. 2, which is constructed by 
superposing two tracings of photographs of successive horizontal sections 
1 The bark of S. mamillaris was found in such a good state of preservation that not only were 
the twin bundles of the leaf-trace shown, but the ligule was found in situ for the first time (H. Cn. 
531, 8). Cf. Arber and Thomas : Ann. Bot., xxiii, p. 514. 
2 Zeiller : Ann. d. Sc. Nat., Bot., 6 e ser., vol. xix, p. 256, 1884. 
3 Kidston : On the Fossil Flora of the Yorkshire Coal Field (second paper). Trans. Roy. 
Soc. Ed., vol. xxxix, Part 1 , 1897. 
4 Goldenberg : Flora Saraepont. foss., Heft I (1855) an d Heft II (1857). 
6 For convenience of reference, see Scott’s Studies, Fig. 96, a and B, but the original figure 
more closely corresponds with Mazocarpon. 
